The adoption by Congress of major statutes regulating the environment, workplace, and consumer transactions, beginning in the mid-1960s, has been seen by critics as granting too much authority to the federal government at the expense of the states. The critique of federal social regulation initiatives questions not only whether such policy interventions can be justified per se, but as importantly, whether congressional preemption itself is appropriate. Presidents Richard Nixon and Ronald Reagan sought specific legislative and policy changes aimed at shifting formal authority away from Congress and back to the states—a “new federalism” to reverse the expansion of federal authority. At least rhetorically (though not necessarily substantively), President George W. Bush has taken a similar stance. But the perceived need to check federal authority is not the sole purview of conservatives; President Jimmy Carter supported a significant program of economic deregulation, and President Bill Clinton oversaw initiatives to devolve federal authority as part of a broader reform of federal public management practices.

The broad contours of this tension between federal and state governments are well known by those who follow policymaking in the United States. What is less well understood is how the specific mechanisms that define the distribution of policy authority in a federal system actually function in practice. Joseph Zimmerman's Congressional Preemption provides a definitive account of preemption statutes, how they are used, and to what consequence across a range of regulatory policy domains. His efforts are important because to understand preemption is to understand a central dynamic factor in American regulatory federalism. Though the subject of congressional preemption has not attracted significant scholarly attention, Zimmerman's account of the nature of federal–state regulatory arrangements convincingly demonstrates that federalism and regulation scholars will gain much by directing more attention to the topic.

In addition to an examination of judicial evaluation of preemption statutes and of their fiscal implications, the book presents three key themes. The first and most important theme is that the two prototypical conceptions of dual and cooperative federalism are unable to adequately identify and explain the complexity and mutability of policymaking relationships between levels of government. Preemption is critical to these relationships, but it is not a simple construct. Preemption can be complete, where Congress removes all regulatory powers from a state and its political subdivisions. It can be partial, where a statute completely occupies a segment of a regulatory domain or where Congress establishes minimum regulatory standards that state governments must meet. And it can be contingent, where applicability depends on a state's actions. Because the Constitution provides Congress with broad authority to restructure the federal system, it is perhaps no surprise that Congress has utilized these different types of preemption actions so frequently in responding to perceived national problems and social demands. In recent decades, Congress has altered the basic nature of federal and state regulatory responsibilities and behavior. In essence, Zimmerman argues, we have moved beyond cooperative federalism to a new model that is generally more coercive, though one that still exhibits cooperative elements.

As a consequence, what is needed today is a more general theory of federalism—one that characterizes and explains how and why the different forms of preemption are used in particular instances and to what effect. Zimmerman does not actually develop such a theory but does offer the broad outlines of what such theoretic development must address. However, these postulates do not actually point to the general conditions under which readjustments to the balance of policy authority will occur. Thus, there are limits to what the reader can infer from his argument about the particular shape a revised theory of federalism should take.

A second theme of the book is that the manner by which preemption statutes are employed is critical to the assessment of whether nationally established policy goals are achieved. There are significant constraints on their utility (e.g., technological limitations may preclude the realization of a regulatory goal), and Zimmerman shows that several major preemption statutes have not accomplished their stated aims. The most successful approach is the one that establishes minimum federal standards and gives state government enforcement responsibility (with federal monitoring). The author suggests that allowing primacy has increased the responsibilities of both state regulators and state legislatures, which paradoxically has forced the states to do more. But does this represent something akin to a unitary system, as he suggests? This seems a bit overstated if one considers that even in the case of “successful” partial preemption statutes, state governments have considerable leeway in developing and enforcing regulatory implementation plans. In fact, the federal government has often been rather reluctant to seriously sanction state governments who are either intentionally or unintentionally ineffective in executing their regulatory responsibilities.

The final theme relates to responsiveness and responsibility. The degree to which Congress is responsive to the demands of state and local governments affects preemption choice. Preemption also shapes how policy responsibility is perceived and understood both by government actors and by private interests. These are difficult issues to sort out. State and local governments typically bristle at congressional mandates, but ultimately they must successfully engage the political process to safeguard their authority. Regulated industries see a trade-off between stringency and consistency of regulatory standards. Public interest groups often favor strong federal action, though the track record of complete preemption is not particularly strong. Zimmerman engages all of these complexities in grappling with the products of preemption efforts.

Ultimately, these issues of responsiveness and responsibility, of goal achievement, and of a theoretic characterization of regulatory federalism are fundamental issues to the study of American public policy. Congressional Preemption offers important insight into how the mechanics of policymaking authority shape the substance and politics of policy outcomes. Understanding the critical nature of preemption is an important starting point for a clearer understanding of federalism generally and regulatory policy in particular.