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Domestic Influences on International Trade Policy: Factor Mobility in the United States, 1963 to 1992

Published online by Cambridge University Press:  04 January 2006

Jeffrey W. Ladewig
Affiliation:
University of Connecticut, Storrs, jeffrey.ladewig@uconn.edu

Abstract

The constituent influences on congressional voting patterns for trade policy have long been an important field of study. A central theoretical component (explicitly or implicitly) of all these studies is the level of factor mobility that defines which constituent coalitions will form and how they will be affected. Yet the recent literature offers contradictory evidence on the current level of factor mobility. Using an original data set of economic demographics of House districts and the roll call votes of U.S. House members on trade policies from 1963 to 1992, I argue that factor mobility was relatively low in the 1960s and 1970s but was rising. The relative level of factor mobility, then, reached a pivot point in the late 1970s and was subsequently relatively high in the 1980s and 1990s. I check the robustness of these results on the expected strength of the political parties in supplying these policies and the effects of divided government.I would like to thank Oksan Bayulgen, Sam Best, Mark Boyer, Stephen Bronars, Walter Dean Burnham, Virginia Hettinger, Alan Kessler, Peter Kingstone, Tse-Min Lin, Robert Moser, Phil Paolino, Dennis Plane, Howard Reiter, Brian Roberts, Ken Scheve, Lyle Scruggs, Mathieu Turgeon, the editor of IO, and two anonymous reviewers for their helpful comments and suggestions. Any errors that remain are, of course, my own.

Type
Research Article
Copyright
© 2006 The IO Foundation and Cambridge University Press

As globalization is increasingly affecting individuals, the domestic influences on international trade become especially important to understand. A central aspect of any constituent-based political-economy model of trade policy, explicitly or implicitly, is a theory of intersectoral factor mobility. The level of factor mobility—or the degree of factor specificity—defines the ease with which the factors of production can move among sectors of the economy. As factor mobility varies, so do the expected constituent coalitions for and against trade liberalization. The level of factor mobility, then, is an essential tool in developing theoretical and empirical models of constituent interests for trade policy. Furthermore, the level of factor mobility also has significant effects on an individual's income, the depth and breadth of the economic impact of globalization on society, the ability of the political parties to represent the vying constituent coalitions, as well as on the volume of international trade itself. Thus whether factor mobility is relatively high or low has far-reaching but vastly different consequences in the economy, in society, and in politics.

The level of factor mobility cannot be measured directly. With a few notable exceptions, it and the appropriate modeling of constituent coalitions for and against trade policy are too often assumed or not considered. Thus it may not be surprising that an examination of the literature on recent U.S. trade policy and constituent coalitions does not produce, in the aggregate, consistent conclusions. Although some studies have shown evidence that factor mobility is consistent with it recently being relatively low,1

See, for instance, Hiscox 2002a and 2002b; Magee, Brock, and Young 1989.

others have reported evidence that is consistent with its being relatively high.2 Hiscox provides probably the most extensive studies of factor mobility to date.3

See Hiscox 2001, 2002a, and 2002b.

He analyzes factor mobility in six countries, including the United States, over a span of nearly two centuries. He too finds evidence of high and low factor mobility during his most recent pooled time period for the United States, 1970–94.4

See Hiscox 2002a, 154, and 2002b, 602–3.

In this study, I try to bridge the theoretical and empirical gaps manifested by the seemingly inconsistent findings among the multiple studies that have addressed constituent interests and trade politics in the United States from 1963 to 1992. To do so, I directly test whether factor mobility is relatively low or high and if it changes.5

Determining the precise level of factor mobility is nearly impossible. The purpose here is to provide an insight into the general trend.

Using U.S. House of Representative roll call voting and an original data set of constituent economic demographics at the level of House districts, I argue that factor mobility was indeed relatively low in the 1960s and 1970s. It gradually rose, however, and reached a pivot point, or critical threshold, near the end of the 1970s that tipped the balance between relatively low and relatively high factor mobility. Factor mobility remained relatively high in the 1980s and 1990s. In other words, I show that factor mobility is a societal characteristic that takes years to gradually change but has profound effects throughout the economy and politics.6 I also demonstrate that constituent economic coalitions significantly affect legislative voting behavior in a manner consistent with the predictions of the economic theories of trade policy. Finally, on an expanded set of international economic policy votes, I check (1) the robustness of the findings on the strength of the political parties in supplying these policies and (2) the influence of the partisan control of the branches of the federal government. The robustness results confirm the expected political consequences of a change in the relative level of factor mobility.

Five sections follow. First I present the two main economic theories of factor mobility and constituent interests for international trade, and I examine the aggregate inconsistencies in the current literature. Next I explain the construction of the data set employed and the study's hypotheses. Third I report and discuss the findings; and fourth check the robustness of the findings. I conclude with the theoretical and practical implications of the study.

Constituent Trade Interests and Factor Mobility

Constituent trade interests are modeled by one of two well-established economic theories: the Ricardo-Viner or the Stolper-Samuelson theory. For the purposes of this study, there are three general but critical differences between these models. First, the Ricardo-Viner model assumes that factor mobility is low; the Stolper-Samuelson model assumes that it is high. Second, the models predict different constituent coalitions in society, based on the way that gains and losses in factor income are distributed. The Ricardo-Viner model predicts sectoral constituent coalitions; the Stolper-Samuelson model predicts factoral constituent coalitions. Because factor mobility cannot be both high and low at the same time, the two models are, by definition, mutually exclusive. Over time, however, factor mobility can gradually change and, hence, can exhibit characteristics of a continuous variable.7

Hiscox 2002a and 2002b, for instance, makes a similar argument.

Third, the coalitions predicted by both economic models vary considerably in form. When factor mobility is high, the resulting factoral constituent coalitions are, by definition, relatively homogeneous; when factor mobility is low, the resulting sectoral constituent coalitions are, by definition, relatively heterogeneous.8 This conclusion is based on the economics assumptions of each model.

Specifically, the Stolper-Samuelson model assumes that the factors of production—labor and capital—are mobile, and thus the model derives preferences and predicts coalitions based on the relative abundance or scarcity of the factors.9

Consistent with many recent works on the United States, the factor of land is omitted.

The more abundant factor will be advantaged by the comparative gains of international trade and experience income gains. Therefore, the economic interest of the owners of the abundant factor is to favor an increasingly liberal trade environment. Owners of the abundant factor and the firms that intensely employ it will not only gain absolutely from liberalization but also relative to the owners of the scarce factor and the industries that intensely use it because of the redistributive income effects between them.10

See, for instance, Mayer 1984, 973–74; Scheve and Slaughter 2001a, 48–51.

In the United States, given its economic development and current endowments, capital is the abundant factor and labor is relatively scarce.11

See, for instance, Rogowski 1987 and 1989.

Accordingly, capital and capital-intensive firms derive greater long-term benefits from free trade. At the same time, labor experiences greater competition and falling wages, and therefore favors policies that decrease the exposure of the domestic economy to the international economy.

The Ricardo-Viner model assumes that the factors of production are “sticky” and cannot be reallocated swiftly to more efficient sectors of the economy.12

See Alt and Gilligan 1994 for an excellent description of the full logic of the Stolper-Samuelson and the Ricardo-Viner models.

As such, labor and capital will not be competing against each other. In other words, capital and labor in the same sector share the same fate. Each will either be similarly advantaged or similarly disadvantaged depending on the sector's competitiveness in the domestic and international economies. In consequence, the coalitional cleavages will develop not along factoral but sectoral lines (export-competitive versus import-competing industries). Specifically, export-competitive industries will experience income gains from free trade and so favor trade liberalization; import-competing industries will not. Thus in the United States, when factor mobility is low, sectoral (that is, industry) divisions will form; when factor mobility is high, factoral (that is, class) divisions over trade liberalization will form.

The Ricardo-Viner and the Stolper-Samuelson theories are ideal-type theories. Using these models is empirically useful, as I discuss below, even though the actual level of factor mobility is unlikely to conform to their idealized assumptions. Instead, because the level of factor mobility is likely to gradually change over time, it is a secular trend.13

As the actual level of factor mobility gradually moves along a continuum between the two ideal types, there should be a pivot point that distinguishes the two. On one side of the pivot point, factor mobility is relatively low; on other side, it is relatively high. As the median voter's economic interest is tipped from one side to the other, there should be predictable and observable economic and political implications. The level of factor mobility, however, is not directly measurable. It is usually indirectly inferred from these predictable and observable economic and political manifestations, such as the significance of sectoral or factoral variables that influence reelection-minded legislators on trade policy. The aggregate conclusions from such political economy studies of trade policy, however, offer contradictory arguments or evidence on the recent balance of the relative level of factor mobility in the United States. Some have reported evidence of sectoral influence on congressional lobbying and voting behavior.14 Others have reported factoral influences.15 Still others have found evidence of both: exporters and importers, as well as labor and business groups, have had a significant influence.16 There are good reasons, though, why studies have varied so much in their conclusions.

First, most of the studies are concerned not with determining the relative level of factor mobility but with modeling other phenomena. In such cases, factor mobility is frequently assumed, if it is considered at all, to be either low or high. For this reason, the tested constituent economic variables may represent just one of theories, both theories, or parts of each. Because the two models are theoretically mutually exclusive, however, methodological concerns arise when the two models are tested simultaneously. Nonetheless, because factor mobility can vary continuously between the two ideal-type models, it is possible that both sectoral and factoral variables may be significant. As this study emphasizes, however, the balance between relatively low and high factor mobility has important political and economic implications that are best informed by evaluating the comparative performance of each model.

Second, in that the relative level of factor mobility varies, it is possible that at some point during the thirty years that the balance between the two ideal-type models has changed. For instance, empirical evidence may show that during one Congress sectoral influences are more significant and during a subsequent Congress, factoral influences are more significant. This would be theoretically consistent only if the relative level of factor mobility has also changed accordingly. Similarly, if roll call votes are pooled together over a time period in which the balance between relatively low and relatively high factor mobility changes, the tests may produce seemingly contradictory results.

Third, the scope of studies on the domestic influences on trade policy range from analyses of a single roll call vote in one Congress to analyses of roll call votes over nearly two centuries. Given the limitations of available data, particularly for the latter, some of the studies have used state-level data to predict voting patterns in the House. Though this may provide uniformity over time, it raises concerns of ecological fallacies and spurious results.

The current literature has provided valuable results, but this study differs from and contributes to the literature in at least three ways. First, to accurately model the effects of constituent interests on the voting behavior of members of the House, I use House-district-level economic data and analyze each of the fifteen Congresses individually. I use U.S. Census labor and economic data on each of the twenty two-digit Standard Industrial Classification (SIC) manufacturing sectors, and national data on exports, imports, and capital to create a data set of economic demographic variables for each House district over the thirty years for each of the factoral and sectoral coalitions for and against trade liberalization. Testing data across consistent geographic units has been lacking, largely because of the difficulties in collecting and coding disaggregated Census data. This data set, however, provides unit consistency between detailed district-level constituent economic interests over time and House roll call voting.

In addition, the district-level economic variables that I employ discretely capture each of the four possible constituent coalitions: export-competitive versus import-competing sectors or capital versus labor. These four coalitions can be considered input variables that influence rational legislators and can be used to reveal their preferences.17

The use of revealed preferences is a common technique in analyzing trade policy. See Bailey and Brady 1998; Bailey, Goldstein, and Weingast 1997; Gartzke and Wrighton 1998; Gilligan 1997; Irwin and Kroszner 1999; Hiscox 2002a and 2002b; Magee, Brock, and Young 1989.

Others have used variables that represent the output from trade policies and factor mobility, such as wage rates and corporate profit data.18

See, for instance, Hiscox 2002a and 2002b; Kaempfer and Marks 1993.

Under pure neoclassical assumptions, these variables would bear witness to the pressures of international trade in the same way that the input variables would conform to the results from revealed preferences. However, there are reasons to question the reliability of output variables because they are also directly affected by domestic policies, such as minimum wage laws and corporate tax policies. Because government policies may alter the economic equilibrium,19 it is possible that these data are more likely to produce a “false positive.” One way to avoid such difficulties, then, may be to ask individuals directly what their trade preferences are.20

See, for instance, Rodrik 1995; Scheve and Slaughter 2001a and 2001b.

This avoids indirect analyses and endogenous outcomes. Although this is certainly true, other hurdles arise with public opinion surveys. For instance, the American National Election Survey, the most reliable public opinion survey of political preferences over time, has not consistently asked trade questions in all of the years included in this study. To be sure, there are other means of estimating the level of factor mobility; however, using constituent coalitions (input variables) to determine the revealed preferences of rational legislators is the most reliable and readily available method in this case.

The second difference between this study and many of the previous studies is the concentration on determining the balance between relative low and high factor mobility. Significant exceptions to this include.21

See Hiscox 2002a and 2002b; Scheve and Slaughter 2001a and 2001b. Scheve and Slaughter 2001b analyze the 1993 American National Election Survey and find evidence of factoral influences. Though the year 1993 follows the last year of this study, it is included in Hiscox last time period of 1970 to 1994. Similar to some of the cited studies, they come to different conclusions.

Identifying the level of factor mobility may inform previous trade politics studies of possible omitted variables and guide future studies.

The third difference between this study and many of its forerunners is its extension of factor mobility's predictable political consequences: in particular, the ability of political parties to consistently and coherently represent constituent interests, as well as the effects of divided government on trade liberalization. Analyzing two political consequences of changes in the balance of the relative levels of factor mobility provides a stronger theory and a robustness check on the initial empirical findings. Furthermore, the inclusion of political parties and divided government in the analysis aids in accounting for politically endogenous outcomes.

Factor mobility affects political parties by changing the relative level of homogeneity of constituent coalitions.22

See Alt and Gilligan 1994, 188; Hiscox 2002a, 36, and 2002c, 7–8.

To see this, a return to the ideal-type models is appropriate. When factor mobility is high, the disadvantaged factor (labor in the U.S. case) can change its competitiveness only by altering its relative scarcity—a process that would mostly likely take decades. Furthermore, the costs and benefits of international competition extend beyond the tradable industries to all other industries as well. For instance, because labor in tradable industries is predicted to experience downward pressure on wages and greater insecurity, there will be additional negative pressures on labor in all industries. In this case, the costs and benefits of economic liberalization become relatively nonexcludable as the number of those either advantaged or disadvantaged expands across society. Moreover, the class-based pressures on the redistribution of factor income may align with other typically partisan class-based interests and provide a potent political alliance for each party. The effects of high factor mobility, then, extend beyond the tradable sectors of the economy—and even trade policy—and can unite broad interests into relatively homogeneous and polarized coalitions. In this way, as Alt and Gilligan conclude, “there really seems to be a natural affinity between the Stolper-Samuelson model and majoritarian politics”23 such as strong political parties.

Alternatively, when factor mobility is low, an industry that is disadvantageously positioned in the international economy may quickly find its competitiveness changed through, for instance, technological advances. Also, the costs and benefits of international competition are largely limited to the exporting and importing industries. As the income effects are distributed across just the tradable sectors and not more broadly between the classes, there are few income externalities in the nontradable industries. Hence, the sectoral constituent coalitions produced are characterized by fragmented and ephemeral alliances: in other words, they are heterogeneous. Consequently, periods of relatively low factor mobility produce relatively weak constituent coalitions on issues of trade liberalization and, consequently, each party will have a relatively weak constituent foundation on which to base policy alternatives.

In sum, the balance of the relative level of factor mobility affects the degree of constituent homogeneity on trade policy issues.24

The overall homogeneity of partisan constituent coalitions and the strength of the political parties have many contributing influences. This study focuses on just one: factor mobility.

The overall degree of constituent homogeneity significantly also affects the degree of homogeneity of the political parties: the greater the intraparty homogeneity and the interparty polarization, the stronger the parties will be.25

This theory is referred to as Conditional Party Government. See, for instance, Aldrich 1995; Aldrich and Rohde 2001; Rohde 1991.

This implies that when factor mobility is low, “partisanship is likely to be irrelevant because each party tends to represent multiple interests groups with different preferences.”26 When factor mobility is high, “parties should be unified internally on trade and divided [between] each other along class lines.”27

Ibid., 99. Hiscox 2002c, 7–8, makes this pair of arguments as well: low factor mobility facilitates weak parties and high factor mobility facilitates strong parties.

This conclusion is further supported if the parties broadly represent class interests across other issues.28

See, for instance, Hibbs 1977; and Sundquist 1983.

If congressional voting for trade policy is along sectoral lines, then party unity is naturally expected to be less than if voting for trade policy is along factor lines.29

I would like to thank the editor for emphasizing this point.

The introduction of party politics, however, raises the important and much debated issue of the effects of partisan control of branches of the federal government; in other words, the effects of divided government on trade liberalization. For instance, O'Halloran and Lohmann and O'Halloran argue that legislators in unified governments are more likely to grant trade-making authority to the president, and that legislators in divided governments are less likely to do so.30

Karol, on the other hand, stresses the role of “Presidential liberalism”31

Karol 2000. Specifically, since the passage of Reciprocal Trade Agreement Act in 1934, presidents have tended to support freer trade. See, for instance, Bailey, Goldstein, and Weingast 1997; Destler 1995; Gilligan 1997.

and partisan constituent coalitions and preferences. Because of these, Karol argues, “presidents from the protectionist party gain from divided government, and those from the liberal party are harmed by it.”32

Karol 2000, 841.

A wrinkle in this, though, is that free-trading Democrats of the 1960s had become protectionists by 1980, while protectionist Republicans were becoming consistent free traders.33

See, for instance, Gibson 2000; Keech and Pak 1995.

These studies on divided government, however, understate or do not address the relative level of factor mobility and the changing strength of the political parties. Once the latter are considered, then it is logical to theorize that the effects of unified/divided government matter most when the parties are strong and stand for clear and consistent policy alternatives. Therefore, the effects of unified/divided government ought to be mitigated when factor mobility is low because the relatively heterogeneous constituent interests for trade policy weaken the party-constituency bonds. Conversely, the effects of unified/divided government ought to be more prominent when factor mobility is high because of the relatively homogeneous and polarized party-constituency bonds. Even though the relative free-trading position of the president may also be affected by partisanship,34

a general degree of presidential liberalism is assumed. Thus if the parties are strong and the majority congressional party consists of protectionists, divided government should be negatively correlated with trade liberalization; if the majority congressional party consists of free-traders, then divided government should be positively correlated with trade liberalization.35

This general theoretical construction depends on the position of the status quo and does not consider other possibilities. A more extensive discussion, however, is beyond the scope of this article.

This construction largely corresponds to Karol's model (2)36

Karol 2000, 827–29, fn. 15.

and is similar to the constructions used by Schnietz and Bailey, Goldstein, and Weingast.37 If the parties are weak, then both of these effects should be mitigated.

Data and Hypotheses

The rational decisions of reelection-minded legislators are commonly used to reveal the preferences of their constituents. In this case, the influence of constituent coalitions on legislators' trade policy roll call votes can be employed as a measure of the relative strength of sectoral and factor coalitions as a proxy for the relative level factor mobility. Thus I use a dependent variable of roll call votes on trade policy in the House from 1963 to 1992 for all of the initial regressions.38

The time period is chosen for two reasons. First, it begins after the release of the 1960 U.S. census and the subsequent House reapportionment. The 1960 census provides substantially better data than any time period before 1960. The economic data are not available for the entire 1993 to 2002 period, thus they are not included.

For each of the fifteen Congresses, I chose the most important trade policy issue as designated by Congressional Quarterly, such as the Trade Act of 1970, the Trade Reform Act of 1974, the Omnibus Trade Bill of 1986, and the fast track vote in 1991.39

To ensure that there was at least one bill for each Congress, a few commodity specific bills had to be included. This is not optimal. However, most of the bills, if not all, were debated in the House in terms of the direction of national trade policy. See the Congressional Quarterly Almanac various years for the determination of “important” legislation and the substance of the debates.

If there were multiple votes on the same trade legislation, I used the roll call vote that most directly and broadly invoked trade policy without nongermane amendments or components and that also had at least a minimal amount of competition.40

A minimal amount of competition is defined as at least 100 yea and nay votes for each roll call.

The votes selected largely overlap and expand the roll call votes used in other studies of trade policy during this time period.41 For example, in Hiscox's most recent pooled time period, 1970–94, he analyzes just six House roll call votes to estimate the level of factor mobility for his twenty-four-year period.42 Of the six, only four overlap with the slightly different time period analyzed in this study, 1963–92. Votes on each of his four trade acts are included in the fifteen roll call votes analyzed in this article. Each vote was then coded as proliberalization if the bill formally supported trade liberalization or actually attempted to decreased trade barriers. All votes are then assigned the value of 1 if the representative voted in favor of liberalization or a 0 if not.43

Only votes of yea or nay are recorded. All other (non)votes are coded as missing.

Appendix 1 lists all the roll call votes used and how they were coded.44

At first, only one vote is analyzed in each Congress to facilitate the specific requirements of the statistical tests used. See the methods section below.

The two economic models of factor mobility suggest that constituent divisions will either be along sectoral lines if factor mobility is relatively low or along factoral lines if it is relatively high. For each division, there are interests that are advantaged by liberalization and interests that are disadvantaged. Thus there are four possible economic coalitions (in two exclusive groupings) for trade policy interests: export-competitive industries versus import-competing industries (sectoral division) or capital versus labor (factoral division). The former in both cases is expected to support trade liberalization. From this I am able to construct specific assumptions and hypotheses. First I assume that the two coalitions that are advantageously affected by trade liberalization (exports or capital) will positively influence legislators' votes for trade liberalization. Second I assume that the two coalitions disadvantageously affected (imports or labor) will negatively influence legislators' votes for trade liberalization. Third I expect that the sectoral variables will better characterize the 1960s and the 1970s. Fourth I expect that the factoral variables will better characterize the 1980s and 1990s. In other words, I expect that factor mobility was relatively low in the 1960s and 1970s, but was rising and reached a pivot point in the late 1970s. Subsequently, factor mobility has been relatively high in the 1980s and 1990s.

H1: I expect that the sectoral variables will better characterize the 1960s and 1970s

H2: I expect that the factoral variables will better characterize the 1980s and 1990s

The variables for exports, imports, and capital are all constructed using a similar method that creates a unique score for each congressional district for each Congress for each variable. In general, district-level economic demographic data are weighted by a measure of U.S. exports, imports, or capital stock. Bailey, Goldstein, and Weingast and Irwin and Kroszner use a similar variable construction to represent constituent economic interests.45

Specifically, the base district-level economic data record the number of each of the twenty manufacturing industries (based on each of the two-digit SIC codes) in each congressional district for each year from 1963 to 1992.46

This is the primary difference from the constructions of Bailey, Goldstein, and Weingast 1997; and Irwin and Kroszner 1999. The former also uses the total number of industries but includes an additional weight of total number of manufacturing employees; see Bailey, Goldstein, and Weingast 1997, 337. The additional weight is not used here because it is the labor variable. The latter uses sectoral-based product output but also tests a measure that approximates Bailey, Goldstein, and Weingast's; see Irwin and Kroszner 1999, 669. The two measures are highly correlated and produce similar results, see Irwin and Kroszner 1999, fn. 29. The present choice of construction was also constrained by the availability of county- and/or district-level data over the thirty-year time span.

These data are then weighted to account for the national-level economic impact or importance of exports, imports, or capital investment. The export and import weights are the product of the annual national value of the exports or imports, respectively, for each of the twenty manufacturing sectors divided by the annual total domestic value of production for the sector.47

The same weight construction is used in Bailey, Goldstein, and Weingast 1997; Irwin and Kroszner 1999.

For example, if in 1968 textile manufacturers produced $1 billion worth of textiles and exported all of it, then the weight for export competitiveness would be 1.0; if the textiles manufacturers exported only $100 million of the $1 billion worth of production, then the weight for export competitiveness would be 0.1. For imports, if there were $2 billion in textile imports in 1968 and domestic manufacturers still produced $1 billion worth of textiles, the weight for import competition would be 2.0. For each manufacturing sector, the base congressional economic data are then multiplied by the corresponding annual weight for export competitiveness or import competition. Each manufacturing sector's scores are averaged for each two-year period corresponding to each Congress; then the sectors are aggregated. A single score is produced for each House district for each Congress that measures the local impact of exports and imports.

For the capital variable, the weight is the national level of the current-cost gross stock of fixed private capital for each of the twenty sectors for each year measured in millions of dollars. The annual capital stock for each sector is then multiplied by the base congressional economic data by sector for each year. Same as the construction of the exports and imports variables, the sectors are averaged for each Congress and aggregated across sectors to produce a unique score of capital investment for each congressional district for each Congress. This measure is an improvement over most other measures because it uses the same base congressional economic data as exports and imports, thereby making comparisons more reliable. Moreover, it better captures the level of capital investment in manufacturing sectors at the congressional-district level. For the labor variable, the labor figures for the twenty manufacturing industries for each congressional district are available. I simply sum the twenty figures and hence a composite index is not needed. The annual labor data are then averaged across the two years that correspond to each Congress. For the regressions, the capital and labor variables are multiplied by a scalar of 1/1000000 and 1/10000, respectively, so that the coefficients are easier to display. See Appendix 3 for details and data sources.

Methods and Results

The first step in testing the hypotheses is to determine which economic model best fits the data on constituent interests—in other words, to determine whether factor mobility is relatively low or high and when the balance between the two may change. Because the ideal types of the economic models are mutually exclusive, one of the models cannot be reduced to the other by a set of linear transformations. As such, the two economic models are considered nonnested and should not be regressed together.48

See Davidson and MacKinnon 1981; Greene 1997, 364–69; Johnston and DiNardo 1997. For a specific discussion of nonnested models applied to international relations, see Clarke 2001.

For instance, assume one has two trade models, where Hrv is the model under the ideal-type assumptions of low factor mobility and Hss is the model under the ideal type assumptions of high factor mobility. Then one would write:

where X1 and X2 are the exports and imports variables, and X3 and X4 are the capital and labor variables.49

For simplicity, the models are presented in a generic functional form and the intercepts are omitted. The same error structure is assumed across models.

If β3 and β4 are restricted to 0 in Hss, for example, Hss does not equal Hrv because of the fundamentally different assumptions and variables. As such, the two equations are defined as nonnested.

Assume, however, that one were to test a third “supermodel,” Ht, which is a combination of the Hss and Hrv. Then, one would write:

Here one is assuming that the models are nested because, for example, if the coefficients of the Hss model, β3 and β4, are restricted to 0, then Ht is the same as Hrv. Model Ht, though, makes the contradictory assumption that factor mobility can be both low and high. This obviously cannot be the case. Thus the two different and opposing theories necessitate two different models: Hrv and Hss. Clarke demonstrates that nonnested models regressed together in one “supermodel,” such as in Ht, has the potential of producing unreliable results.50

The difficulty, then, becomes comparing the two models head-to-head. To do so, I use the same procedure, the J-Test, as did Hiscox.51

Hiscox 2002a and 2002b.

This procedure uses an indirect linear combination of the two models to determine which one (if either) better fits the data. Specifically, the predicted values from the first economic model, Hrv, are included in the second economic model, Hss, as a new variable and retested; the process is then repeated with the predicted values from the second model retested in the first. The coefficients that are produced for the predicted value variables are essentially the weight given to that model and can be directly compared. If only one of the two coefficients for the predicted value variables is significant, then that model outperforms the other (because the insignificant coefficient indicates that that model's weight cannot be distinguished from zero). If both coefficients are significant or neither is significant, then the result is indeterminate and the appropriate model cannot be assessed.

The J Test, then, compares the ideal-type theories and generally produces a dichotomous result supporting either Hrv or Hss. As a result, if the sectoral model outperforms the factoral model in influencing policy, then it is logical to conclude that factor mobility must be relatively low. Conversely, if the factoral model outperforms the sectoral model, then factor mobility must be relatively high. This solves the problem of comparing nonnested models but raises another issue. The dichotomous result belies the gradual change that factor mobility as a secular trend is expected to display. Instead, it simply determines which side of the balance between relatively low and relatively high factor mobility the data better fit. Thus a shift in the balance may appear to be discontinuous even if it is not. Although less than optimal, this is a methodologically necessary concession. I attempt to accommodate this, however, through a graphical examination of the probability of each model's statistical significance.

Because the roll call vote takes only the value of 0 (antiliberalization) or 1 (proliberalization), probit is used to estimate each model. For each Congress only the economic variables from the models are regressed on the roll call vote. As discussed above, other factors such as the legislator's party affiliation and divided government may also influence voting behavior on trade policy. These additional variables will be included in the robustness checks, but they are omitted from the J Tests to maintain consistency with other studies of factor mobility. Specifically, Hiscox estimates the effects only of constituent economic variables and argues that he “exclude[s] [controls for party affiliation] to provide the clearest imaginable test between the class and the industry-group models.”52

Given the importance of his work on this subject, it is necessary to maintain this comparability initially. Table 1 reports the results from the J Tests.

J Tests of models of factor mobility, 1963–92

The results shown provide a measure of the general trend of factor mobility through the applicability of each model. In ten of the fifteen Congresses, the null hypothesis of only one of the two economic models is rejected. This allows one to say which model is statistically more appropriate. In the remaining five Congresses, one cannot decipher the applicability of the two models because either both models are significant or neither model is significant. Specifically, from 1963 to 1978, the Ricardo-Viner model is the only model that is accepted and therefore indicates that the data are consistent with relatively low levels of factor mobility. The Ricardo-Viner model, however, is significant in only half of these Congresses (that is, four of the eight Congresses), which may indicate some weakness in the sectoral variables. Conversely, from 1979 to 1992, the Stolper-Samuelson model is the only model that is accepted. This is the case for six of the seven Congresses. Therefore one is provided with strong evidence consistent with relatively high factor mobility. This is further supported by examining the ratio between the pseudo R squares of the Ricardo-Viner model over those of the Stolper-Samuelson model. From 1963 to 1978, the ratio in all but one case is above 1.0, which indicates that the Ricardo-Viner model is able to explain more variance in the data than the Stolper-Samuelson model. The opposite is true from 1979 to 1992. Both of these measures are consistent with the balance between relatively low and relatively high factor mobility reaching a pivot point in the late 1970s, with relatively low factor mobility beforehand and relatively high factor mobility after.

Factor mobility can change over time, but it is highly unlikely that it will radically swing from one Congress to another. Accordingly, two caveats are in order. First, the statistically ambiguous tests may be because of exogenous forces or idiosyncrasies in the individual pieces of legislation that are examined. Particularly given the heterogeneous nature of sectoral coalitions, it is not surprising that aggregate measures of exports and imports are significant less often than aggregate measures of capital and labor. (This is also evident in Table 2.) Second, this may also be because of the sectoral coalitions of relatively low factor mobility gradually weakening and approaching the pivot point between it and relatively high factor mobility. This gradual process becomes more apparent if one graphically examines the data over time; Figure 1 does so by plotting the moving average of the p-values of the z-scores from each model over time. The p-values are the probability that each model is significant; the area below the provided 0.05 line indicates statistical significance.53

Because the moving average is used—in order to mitigate outlying results—the horizontal line at 0.05 does not actually represent statistical significance. It is used only illustratively.

During most of the 1960s and 1970s, the dark line representing the Ricardo-Viner model is consistently below the 0.05 threshold, while the light line representing the Stolper-Samuelson model is not. However, from the early 1970s, the moving average for the Stolper-Samuelson model gradually decreases, overtaking the Ricardo-Viner model during the 96th Congress (1979–80), and then is consistently below the significance threshold beginning in the 99th Congress (1985–86). This evidence better represents a gradually changing secular trend—in this case, from relatively low factor mobility, across a pivot point between the two models, to relatively high factor mobility. In this way, this result is more consistent with expectations than the dichotomous results provided by the J Tests.

Appropriate economic model tested on trade liberalization

Changing levels of factor mobility

Using the pivot point that defines the period of relatively low from relatively high factor mobility, I report in Table 2 the probit results from each of the appropriate economic models that were used to generate the J Test results and Figure 1. Because the evidence was consistent with factor mobility being relatively low from 1963 to 1978, the Ricardo-Viner model (that is, export-competitive versus import-competing industries) is reported for these years plus the 96th Congress.54

The 96th Congress is reported with both the sectoral and the factoral variables because the data indicate that it is the tipping point between relatively low and relatively high factor mobility.

Ten of the eighteen coefficients are significant. Specifically, the statistically significant export coefficients are all positive, indicating support for trade liberalization. In all Congresses but the 94th, the statistically significant import coefficients are negative, indicating their opposition to trade liberalization.55

Imports are significant but positive for the 94th Congress. This is most likely an artifact of the specific legislation analyzed. Particularly, one of the amendments to the Bretton Woods agreement allowed for flexible instead of fixed exchange rates. Given the economic context and the artificially strong dollar in the early 1970s, importers may have believed that floating exchange rates would weaken the dollar and, thus, make imports more expensive, which would, of course, be advantageous to sectors of the economy that experience high import competition. Regardless of the direction of this sectoral variable, the Ricardo-Viner model nonetheless outperforms the Stolper-Samuelson in the 94th Congress.

The J Tests and these results lend evidence in support of the assumptions and Hypothesis 1: districts that are relatively export-competitive support trade liberalization and those that are import competitive generally do not, and the sectoral variables outperform the factoral variables during the 1960s and 1970s.

After 1979 the results from the J Tests are indicative of a relatively high level of factor mobility. Thus the variables from the Stolper-Samuelson model (that is, capital versus labor) are reported. In these regressions, eleven of the fourteen coefficients are statistically significant and all are in the expected directions. Districts with relatively capital-intensive interests favored trade liberalization; those with relatively labor-intensive interests did not. This is consistent with the assumptions and Hypothesis 2. Because the relative level of factor mobility can be derived from the significance of the two models and their specific economic coalitions, these data are also indicative of a gradual trend from relatively low factor mobility to relatively high. Again, there is naturally a pivot point between the appropriateness of the two ideal-type models in which the influence of the sectoral variables of relatively low factor mobility should gradually cease to explain as much variance as the factor variables of relatively high factor mobility. Tables 1 and 2 do not allow one to demonstrate this gradual secular trend well. Instead, they simply allow one to determine which side of the balance the data best represent. Despite this methodological concession, the evidence is consistently indicative of a change in the level of factor mobility from relatively low to relatively high during the late 1970s.

Robustness Checks

One way to test the robustness of these results is to determine if other expected effects of low and high factor mobility are also present. As discussed above, the coalitions predicted by the relative level of factor mobility vary in their relative homogeneity. The sectoral coalitions of relatively low factor mobility are relatively heterogeneous; the factor coalitions of relatively high factor mobility are relatively homogeneous. If the sectoral variables consist of weaker and more ephemeral coalitional partners, then their strength in explaining roll call votes on issues of trade liberalization should also be weaker. I have already provided some evidence that is descriptively consistent with this assumption. The Ricardo-Viner model and its corresponding sectoral variables in Tables 1 and 2 were significant less frequently than the Stolper-Samuelson model and its corresponding factoral variables. This evidence is far from conclusive and could be caused by other affects, but nonetheless, it begins to provide some validity to the results.

To further test the robustness of the results, I expand the analysis to include political independent variables. According to the conditional party government literature, relatively homogeneous constituent interests provide the basis for strong parties overall.56

Alt and Gilligan, Hiscox, and Milner and Judkin extend this logic to the specific case of factor mobility.57 They argue that constituent interests derived from relatively high factor mobility provide the foundations for the political parties to coalesce and offer clear policy alternatives on trade issues. Alternatively, the relatively heterogeneous constituent interests that are present when factor mobility is relatively low weaken the parties' ability to offer clear policy alternatives on trade liberalization issues. To evaluate the ability of the parties to offer clear and consistent trade policy alternatives, I include a party variable: republican. It takes the value of 1 if the House member is a Republican and a 0 if a Democrat.

Brady, Goldstein, and Kessler show that during the late nineteenth and early twentieth centuries—a period that Hiscox argues is also characterized by relatively high levels of factor mobility—political parties had a significant effect on trade policy roll call voting. This effect is independent of constituent economic interests.58

Consistent with these findings, I expect that during the 1960s and 1970s when the above evidence indicates relatively low levels of factor mobility, the variable republican should not have a significant impact on trade liberalization votes. This would indicate that the parties do not statistically differ in their voting patterns, and thus do not offer clear and consistent policy alternatives. Conversely, during the 1980s and 1990s, when the above evidence is consistent with relatively high levels of factor mobility, the variable republican should have a significant impact that is independent of constituent economic interests. This would indicate that the parties do offer clear and consistent policy alternatives on trade liberalization issues. Furthermore, Keech and Pak show that the partisan positions on trade liberalization changed during this time period.59 Specifically, during the 1970s, the Democrats switched from being the party of free trade to the party of protectionism. Consistent with this, I expect that the republican variable will be positively correlated with trade liberalization during the period of high factor mobility.

The other influence on the legislator's vote choice discussed above is the partisan composition of the branches of the federal government. The effects of divided government on trade policy have been extensively debated; these studies, however, have largely overlooked the effects of factor mobility on the constituent interests and the political parties. Extending the logic of factor mobility to the effects of divided government is rather straightforward. If the parties do not offer clear and consistent policy alternatives, then the partisan composition of each branch should be less important. If the parties do offer clear and consistent policy alternatives and, as Brady, Goldstein, and Kessler argue, party strength exhibits a significant and independent effect on legislators' voting behavior, then, divided government should also have a significant and independent effect.60

To evaluate these effects, I create a divided government variable that is coded 0 when the House and the president are from the same party and 1 when they are from opposing parties. Given that the Democrats were the majority party during the entire time period analyzed in this study and that they became the party of protectionism during the 1970s concomitantly with the parties gaining strength, I expect that the divided government coefficient will be insignificant when factor mobility is low, and significant but negative during the period of high factor mobility.61

A study with a theoretical focus on the effects of divided government would benefit from a greater range of cases than can be offered here.

H3: republican is expected to be insignificant during periods of relatively low factor mobility.

H4: republican is expected to be significant and positively correlated with trade liberalization during periods of relatively high factor mobility.

H5: divided government is expected to be insignificant during period of relatively low factor mobility.

H6: divided government is expected to be significant and negatively correlated with trade liberalization during periods of relatively high factor mobility.

Because divided government does not vary within a given Congress, the data must be pooled to assess its impact. In order to use the appropriate constituent economic variables, the data are also divided into periods of relatively low and relatively high factor mobility. Similar to the J Tests, this construction is not ideal because it may obfuscate the gradual nature of any change. I try to accommodate this again by graphically documenting the trends in partisan support for trade liberalization by Congress.

The dependent is again dichotomous, thus as before, probit is used. However, members in one Congress may be the same members in another Congress, and thus the independence assumption is violated. To account for this, I use Huber and White corrections to produce robust standard errors. The first two columns of Table 3 show the results from the regressions of the economic and political variables on the pooled trade votes used above. In the first column, the two economic variables for the Ricardo-Viner model are significant and in the expected direction. However, the coefficient for republican is not significant—also as expected. In other words, the political parties did not provide statistically clear and consistent alternatives on trade policy during the 1960s and 1970s. Given the lack of clear partisan policy positions on trade liberalization, there is little reason to assume that the partisan composition of the branches of government should be significant. As expected, then, divided government is also not significant during the pooled years 1963–78, that are characterized by relatively low levels of factor mobility. Thus when constituent economic interests based on relatively low factor mobility are controlled, the political variables do not have an independent effect. This is consistent with the hypothesis that sectoral coalitions produce weak and ephemeral political alliances and thus do not provide a strong foundation for the parties consistently to offer clear policy alternatives on trade liberalization.

Robustness test of factor mobility

In the second column of Table 3, the factoral variables of relatively high factor mobility are used. Both capital and labor are again significant and in the expected directions. In this case, though, both republican and divided government are also significant, each in its expected direction. The positive correlation between republican and trade liberalization indicates that Republicans more clearly and consistently supported liberalization than did the Democrats. I expected that if this is the case, then divided government should also have a significant effect, as it does. The significant and negative coefficient of divided government indicates that the majority-Democratic House is less likely to support trade liberalization when the president is a Republican. These robustness checks are supportive of the primary findings of a gradual change from relatively low factor mobility to relatively high factor mobility during the 1970s. Moreover, because constituent economic interests are controlled, the results also lend additional evidence to the Brady, Goldstein, and Kessler argument that the manifestations of party strength extend beyond direct constituent representation.62

I add the caveat, though, that the presence of relatively homogeneous constituent interests seems to be a necessary condition, and, in the case of trade policy, that is consistent with periods of relatively high levels of factor mobility.

To further check the robustness of the results, I expand the number and content of the roll call votes used in the dependent variable to ascertain whether the results were merely an artifact of the trade policy votes initially chosen. The number of votes is increased from fifteen to forty-five, a quantity significantly greater than are analyzed in most other trade policy studies. The expanded dependent variable consists of additional trade issues as well as such other international economic policy issues as monetary policy. Changes in monetary policy have a direct effect on the exchange rate, which, in turn, can cause constituent-level economic effects similar to those caused by changes in tariff policy. Bearce and Freiden argue that trade economic models can therefore be used to examine the constituent effects of monetary policy.63

Thus the inclusion of additional international economic policies in the dependent variable is consistent with the theoretical construction presented in this study yet also provides a broader and more strenuous robustness check on the theory and results.

I selected additional roll call votes and coded them using the same guidelines as used in the initial selection of trade policy votes. For each Congress, I included two additional votes that had at least a minimal amount of competition and offered the clearest purchase on the policy issue. I coded each as either proliberalization or antiliberalization. I coded each legislator, then, 1 if he or she voted in favor of liberalization and coded a 0 if he or she voted against.64

Consistent with Bearce 2003, the monetary policy votes were coded as proliberalization if the legislation encourages monetary convergence and antiliberalization if the legislation encourages monetary autonomy.

(See Appendix 2 for a list of the additional votes and their coding.) Then the votes for each legislator were aggregated, creating an index that ranges from 0 to 3.65

This variable could not be easily used in the initial J Tests because the predicted values are based on multiple cut points.

The index allows for greater nuance; in effect, each legislator could also give one-third or two-thirds support for liberalization.66

Only legislators that voted on all three bills for each Congress are included.

Given that this dependent variable is ordered and discrete, I use ordered probit with the Huber and White corrections.

As before, the two models based on the relative level of factor mobility are used; columns (3) and (4) of Table 3 report the results. As expected, the sectoral variables in column (3) do not perform well with the broader dependent variable. Still, when exports is significant, it is positive; imports is not significant. The latter is descriptively consistent with the assumption that weaker coalitions of relatively low factor mobility can experience cross-cutting pressures and hence may be less potent in influencing a broader set of policy issues. Unlike the test on trade votes in column (1), republican is significant in column (3). The negative coefficient, though, is consistent with Keech and Pak's argument that the Democrats were more supportive of liberalization during the 1960s and early 1970s than the Republicans.67

Keech and Pak's 1995.

Even so, the partisan effect is relatively small. For instance, holding all of the other independent variables at their means but allowing republican to vary from 0 to 1 produces the largest probability on the third cut point. Specifically, a Democrat with identical constituent interests as a Republican will be only 4.46 percent less likely to vote in favor of liberalization on all three pieces of legislation. Given this rather weak partisan effect, it is not surprising that the coefficient for divided government is insignificant.

Column (4) reports the results from the period with relatively high factor mobility. All of the variables are significant and in the expected direction. capital is positively and labor is negatively correlated with trade liberalization. As expected, the republican coefficient is also significant but changes direction from the 1963 to 1978 analysis in column (3). In this case, the partisan effect is also much greater. For instance, holding all of the other independent variables at their means but allowing republican to vary from 0 to 1 increases the probability that a legislator will vote in favor of liberalization on all three pieces of legislation by 37.48 percent.68

The cut point at 3 is used again for comparative purposes even though it does not produce the largest probability this time. Instead, the cut point at 0 produces a probability that a Democrat with identical constituent economic interests as a Republican is 50.36 percent more likely to vote against trade liberalization in all three pieces of legislation.

As expected, such a strong partisan effect independent of constituent economic interests creates a circumstance ripe for partisan conflict between the branches of government. It is no surprise, then, that divided government is significant in column (4) and negative: the majority-Democratic House is less likely to support liberalization when the president is a Republican. Even though there are certainly numerous causes of increased partisanship between these two time periods, these results are consistent with the expectations derived from a change in the relative level of factor mobility being at least a parallel and possibly a contributing influence.

Viewing the data graphically for each Congress shows a more gradual pattern of increased partisanship over issues of liberalization than is evident in the split pooled cross-sectional analyses of Table 3. In Figure 2, I plot the moving average of three variables that represent party strength in the House from 1963 to 1992. The dark line is the Average Party Unity (APU) scores, the aggregated difference between the percentages of each party voting yea on each piece of legislation for each Congress. As Rohde argues, this is the best measure to determine how internally united and externally divided the parties are—in other words, how strong they are. The trend displays a significant increase in party resurgence beginning in the late 1970s and early 1980s.69

This trend has led many scholars to declare that the political parties are once again strong.70

Average party unity, 1963–92

The two light lines in Figure 2 (one with square and one with triangular data point markers) are the APU scores for the trade votes and for the international economic policy votes, respectively. Both exhibit a similar pattern over these issues: trending from partisan dealignment to partisan realignment. During the latter, the parties offer clearer and more consistent partisan policy alternatives. The international economic policy APU scores, however, begin to show the partisan realignment sooner than the trade policy APU scores. In both cases, the 1970s is obviously a time of great partisan change. In addition, the trends correspond to the pattern discussed in the decline and resurgence of U.S. political parties' literature, the partisan trade policy literature,71

and the trends displayed in Table 3. In fact, the correlation between the overall APU and the trade votes APU is 0.614; the correlation between the overall APU and the International Economic Policy APU is 0.787. The thirty years analyzed cover a vast terrain of politics and legislation: the civil rights movement, the Vietnam War, stagflation and the oil crisis, Reaganomics and recession, the Iran-Contra affair, and the first Persian Gulf War. So a strong correlation between a specific set of issues and all the issues addressed by Congress from 1963 to 1992 is noteworthy at the very least.

Discussion

The above results both confirm and challenge the existing literature on factor mobility and constituent trade preferences. The results confirm the significance and direction of sectoral constituent interests in the 1960s and 1970s and of factoral constituent interests in the 1980s and 1990s on trade policy. They also clarify some of the aggregate inconsistencies in the literature. For example, Magee, Brock, and Young, Kaempfer and Marks, and Scheve and Slaughter study U.S. trade preferences in one particular time period since 1960.72

Magee, Brock, and Young find evidence that is consistent with low factor mobility in the early 1970s; the others' evidence is consistent with high factor mobility in the 1990s. Under an assumption of constant factor mobility from 1963 to 1992, these conclusions are contradictory. By challenging an assumption of constant factor mobility, however, the findings presented in this article help to rectify these differences. Because the general trend from relatively low to relatively high factor mobility reached a pivot point during the late 1970s, studies of trade preferences of the 1960s and 1970s should find sectoral influences more significant and studies of the 1980s and 1990s should find factoral influences more significant.

Other studies have provided longitudinal analyses of trade preferences. Rogowski, for instance, does not test for variability in factor mobility—and, accordingly, the appropriateness of each economic model.73

He assumes that factor mobility is high but finds some contradictory evidence in the United States from 1948 to the early 1980s.74

Rogowski 1989, 119–21.

Midford expands on this point and notes a number of empirical anomalies in the assumption of high factor mobility: labor in specific sectors, such as “light industries such as textiles, apparel, and shoe manufacturing,” supported protectionism in the 1950s; labor in other sectors, such as the United Auto Workers, continued to support free trade until the end of the 1970s.75

Midford 1993, 538–39.

These instances contradict the assumptions of high factor mobility but fit the expectations of low factor mobility; where export-competitive and import-competing industries are the dominant constituent economic cleavage. Specifically, Midford notes that the logical extension of his alternative model to Rogowski's—the multifactoral model—approximates the Ricardo-Viner model of low factor mobility in the extreme and has some applicability to the United States for the 1950s through the 1970s.76

Ibid., 562–63.

The findings presented in this study for the 1960s through the 1970s are also consistent with Hiscox's findings.77

Hiscox 2002a and 2002b.

He argues that factor mobility in the United States was in decline throughout most of the twentieth century. Despite the century-long trend, he finds some evidence of high factor mobility in his last pooled time period, 1970 to 1994.78

See Hiscox 2002a, 154; Hiscox 2002b, 602–3.

This study and the other studies that find factoral influences in the 1980s and 1990s suggest that, at the very least, his pooled time period may be obscuring a change in the mobility of factors that occurred in the late 1970s.

In addition, I have emphasized two methodological points. First, the inclusion of both sectoral and factoral variables in the same model may lead to erroneous results. To test two competing and nonnested models accurately, alternative statistical procedures are required to discriminate between them. Second, case-unit consistency between the geographic dimensions of the economic and political variables, in this case House districts, produces results that are more reliable. No doubt, this type of detailed economic data is not consistently available for studies such as Hiscox's that cover two centuries. Nonetheless, empirical constructions that are not unit consistent may also obscure trends that are indeed present.

This study, then, provides the case for a gradual increase in factor mobility with the balance between relatively low factor mobility and relatively high factor mobility reaching a pivot point from the former to the latter in the late 1970s. This claim begs the question: What causes factor mobility to change? There are multiple determinants of the level of factor mobility.79

The determinants discussed represent general national level trends. There could, of course, be local contradictions such as housing shortages, additional transportation costs, and the like. The probable presence of such local anomalies ought to have only diminished the reported results.

The most obvious is the costs of moving factors across physical space. As transportation costs decrease so do the costs of mobility, and thus factor mobility will be increasing. For instance, Kim argues that the diminishing U.S. regional differences in income disparity, economic structure, and factor endowments from 1947 to 1990 were caused, in part, by decreasing costs of transportation and communications.80

Kim 1998, 679.

An equally important determinant is the costs associated with moving factors across product space. Kim also argues that firms in the United States during this time period “increased [their] usage of substitutes and recycled inputs.”81

Ibid., 680.

It is assumed that factors become increasingly interchangeable as the costs of introducing new factors across product space become lower; in other words, higher levels of factor mobility. In sum, U.S. factors of production seem to have become physically and practically more mobile during the second half of the twentieth century, partially because of developments in technology and improvements in transportation.

The general economic context also affects the relative level of factor mobility through the decision calculus of individuals.82

Laborers, for example, decide to invest in the optimal type of skill training, either specific or general, depending on the economic environment. In an uncertain world, workers vary their training investment based on expected risk. In an economic environment with low risk (for instance, high employment stability and retention), a worker has an incentive to choose to increase personal returns by specializing. In an economic environment of high risk, however, the same worker foregoes the increased returns of specialization in favor of the greater employment security offered by general skill training. The former decreases factor mobility; the latter increases it. Grossman and Shapiro conclude optimistically: “factor mobility is more likely to be observed when it is most important that factors be mobile.”83

Their conclusion implies that during periods of economic stagnation and increased job churning, one should witness individuals making investment decisions that increase their ability to be mobile. In this vein, Boisjoly, Duncan, and Smeeding demonstrate that from 1968 to 1992, all labor groups except government workers experienced increasing incidence of involuntary job loss.84

Despite the perception of relatively tight labor markets in the 1990s, Farber shows that involuntary job loss rates were even higher in the 1990s than in the 1980s.85 Furthermore, displaced workers that were reemployed suffered “significant earnings declines relative to what they earned before they were displaced.”86

Ibid., 1.

Similarly, the number of union elections and the union voting rates were rather stable during the 1960s and 1970s but decreased precipitously beginning in the early 1980s and continued through the 1990s.87

Ibid., 9.

Union membership rates correspondingly also decreased significantly during the latter time period. Farber and Western argue that “increased global competitiveness and mobility of capital were likely important contributing factors” to these changes in union strength.88 These circumstances did not escape the perceptions of workers either. Using the General Social Survey, Schmidt shows that workers became increasingly pessimistic about their job security from 1977 to 1996. In response, they invested “less in firm-specific human capital and are more concerned about developing general skills.”89

Schmidt 1999, S128.

Dynamic factor mobility is not limited to labor. Grossman also constructs a theoretical model of changing degrees of capital mobility.90

Grossman 1983. See also Brawley 1997 for a direct application of this model to the case of imperial Germany.

The Stolper-Samuelson model predicts that as the relative level of factor mobility increases, the fortunes of labor should decrease and the fortunes of capital should increase. In that vein, Farber and Hallock find that reductions in the labor force from 1970 to 1997 are positively correlated with increases in firms' stock prices.91 It is also not surprising, then, that income disparity between the classes has also greatly accelerated since about 1980.92

Although the theories are clear on this point, the empirical conclusions have been mixed on the extent of trade's influence on growing income disparity. See Slaughter 2000 for a survey of the literature.

The increased income disparity also has been shown to have significantly affected partisanship.93

One economic trend that seems to be at odds with a gradual increase in the level of factor mobility is the tremendous concomitant growth in intraindustry trade. If factor mobility is relatively high, countries that are endowed with abundant capital, for instance, should gain from trade with countries endowed with abundant labor. Intraindustry trade, though, is typically among capital-abundant northern countries. This conventional wisdom, however, has been theoretically and empirical challenged. When technological differences among northern countries are considered, “it is possible to have a strictly conventional [factoral] model in which the volume of North-North trade exceeds that of North–South trade.”94

Davis 1997, 1060.

Davis and Weinstein (2001) further develop the model and test it on ten countries within the Organization for Economic Cooperation and Development (OECD) across thirty-four industry types. The results confirm that intraindustry trade among capital-abundant countries does not violate the factor endowment theories.

Finally, it is important to note that in analyzing aggregate district interests and the revealed preferences of legislators through policy votes, it is difficult to isolate the economic links.95

For an excellent discussion of this, see Magee, Brock, and Young 1989.

This study and all studies similar to it are drawing conclusions about the general trends of economic phenomena while simultaneously invoking (directly and indirectly) political institutions and preferences.96 The inclusion of “political parties” and “divided government” in this study provides an additional check on the robustness of the economic findings by controlling for these political components. The results confirm both the expected economic and political effects of factor mobility. Economically, the influence of sectoral and factoral variables remains significant while controlling for party and divided government. Politically, the significance of a legislator's partisanship and the effects of divided government are correlated with relatively high factor mobility. Logically, other periods of high factor mobility ought to have had a similar potential to generate strong partisan conflicts over trade policy. For example, Hiscox argues that factor mobility was high during the late nineteenth century in the United States.97

Hiscox 2002a and 2002b.

As expected, this was also a period of strong parties offering clear and consistent partisan alternatives on trade policy.98 Given the findings in this article of high factor mobility in the 1980s and 1990s, it is not surprising, then, that Destler has argued that “today's debate over the impact of globalization parallels that over a nationalizing U.S. economy that became heated a century ago.”99

Conclusion

As economic globalization intensifies, the domestic influences on international trade policy become ever more important to understand. A central variable in the formation of domestic trade preferences and constituent coalitions is the mobility of factors. The analysis presented in this article is consistent with factor mobility being relatively low but rising during the 1960s and the 1970s, reaching a pivot point in the late 1970s and subsequently remaining relatively high during the 1980s and the 1990s. Furthermore, the constituent coalitions are shown to influence the voting behavior of legislators in a manner consistent with economic theory. Constituent coalitions of exporters and capital are positively correlated with trade liberalization, and coalitions of importers and labor are negatively correlated with trade liberalization. I have also shown that the level of factor mobility and the coalitions' predicted level of homogeneity are significantly correlated with the strength of the political parties in supplying trade policies and the influence of divided government.

The relationship among constituent interests, trade policy, and political institutions is dynamic and continues to deserve much greater attention. Further study in this area is crucial not only for an improved understanding of the political system but also as a means of better isolating economic phenomena. Toward this end, this study sheds theoretical light on some of the empirical discrepancies currently present in the literature on trade preferences and policy by using a more detailed data set of constituent economic interests and challenging the theoretical assumption of a constant level of factor mobility. Finally, the relative level of factor mobility is likely to have profound effects on the distribution of income as well as on numerous other policy areas: for instance, immigration policy. As such, using factor mobility to explore political and economic phenomena should continue to be a fertile area of research.

Appendix 1: Trade Policy Votes

Appendix 2: Additional Roll Call Votes on International Economic Policy

Appendix 3: Data Sources and Variable Construction Details

The base economic data are constructed from three sources. Together, these sources provide data on the number of the twenty manufacturing industries based on the two-digit SIC classifications (see below) in each U.S. House district for each year from 1963 to 1992. First, for the years 1963 to 1972 (the first two years of the subsequent decade are included because redistricting after that decade's census had not yet occurred), the data are found in the Congressional District Data Book (Districts of the 88th Congress). Here, the data are presented for the twenty manufacturing sectors already aggregated into House districts. Unlike the data for 1973 and after, the Congressional District Data Book provides data only on firms with twenty or more employees. Second, for the years 1973 to 1976, the data are aggregated only at the subcongressional level (that is, county and independent city). The data for the 3,143 subcongressional units can be found in the Census of Manufacturers, 1972. Beginning in 1977, a digital copy of annual data from County Business Patterns, various years, is available at the I.C.P.S.R. Accordingly, from 1977 to 1992, I use the annual data at the subcongressional unit level for each of the twenty manufacturing sectors. Because the annual data are not available before 1977, the base economic data from 1963 to 1972 and from 1973 to 1976 are held constant.

The subcongressional data (1973 to 1992) are then aggregated into their appropriate congressional district. If one of the subcongressional units was entirely contained in one congressional district, it was simply coded for that House district. If one of the subcongressional units is not entirely so contained but divided between two or more congressional districts, the base economic data for the subcongressional unit is weighted by the percentage of the population of the unit that lives in each corresponding congressional district. From 1972 to 1982, the population percentages are calculated using the 1970 Census of the Population, Characteristics of the Population for each state. From 1983 to 1992, the 1980 Census of Population and Housing: Congressional Districts of the 98th Congress for each state is used. In both cases, the base economic data are then aggregated into the appropriate House districts. Together with the House data from the Congressional District Data Book, the base of congressional economic data is created that provides a detailed demographic account of the number and type of manufacturing industries found in each congressional district for each year from 1963 to 1992.

Next, the base congressional economic data is weighted by annual national level economic data for exports, imports, and capital stock, respectively. The data for the value of the exports and imports can be found in U.S. Census Bureau, U.S. International Trade in Goods and Services, series FT-900, various years. The domestic value of production (GDP) by industry is found in the U.S. Bureau of Economic Analysis, Survey of Current Business, various years. The gross stock of fixed private capital is found in the U.S. Bureau of Economic Analysis, Survey of Current Business, various years. For the years 1963 to 1972, the number of laborers in each congressional district as found in the Congressional District Data Book is weighted by the annual percentage of the national rise or decline in manufacturing jobs. For the years 1973 to 1976, the number of laborers in each of the subcongressional units (as found in the Census of Manufacturers, 1972) is aggregated into congressional districts using the same process as described above and is weighted by the annual percentage of rise or decline in manufacturing jobs in each state.

The following are the manufacturing sectors and their SIC number:

20. Food and kindred products

21. Tobacco manufactures

22. Textile mills products

23. Apparel and other textile products

24. Lumber and wood products

25. Furniture and fixtures

26. Paper and allied products

27. Printing and publishing

28. Chemicals and allied products

29. Petroleum and coal products

30. Rubber and plastic products

31. Leather and leather products

32. Stone, clay and glass products

33. Primary metal industries

34. Fabricated metal product

35. Machinery, except electrical

36. Electrical equipment and supplies

37. Transportation equipment

38. Instruments and related products

39. Miscellaneous manufacturing

References

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Figure 0

J Tests of models of factor mobility, 1963–92

Figure 1

Appropriate economic model tested on trade liberalization

Figure 2

Changing levels of factor mobility

Figure 3

Robustness test of factor mobility

Figure 4

Average party unity, 1963–92