The Senate’s fall 2018 confirmation of Brett Kavanaugh cemented a likely Republican majority on the Supreme Court for a generation and drew attention to that institution’s perceived politicization. Scholars, journalists, and members of the public have sought to understand whether these events will undermine the Court’s standing in the eyes of the American people. We are lucky, then, that this same season marked the publication of Michael F. Salamone’s Perceptions of a Polarized Court, a book that addresses these important questions carefully and systematically.

Salamone’s primary interest comes in understanding the ability of the Supreme Court to shape public opinion. Scholars have long sought to understand the conditions under which Americans will accept a displeasing decision from the U.S. Supreme Court and when the Court’s opinion will have enough persuasive heft to alter their opinions on an issue. One major contribution of the book is its systematic approach to addressing all of the pieces that must fall into place before the public’s views can be shaped by the Court’s decision. Salamone persuasively argues that because typical Americans are not avid Court watchers, the public relies on the media to tell them what the Court decided. And when covering the Court, journalists face their own constraints. Not every decision is newsworthy, and journalists have to decide what details to use to teach the public about the Court’s decision. He argues that one particular type of detail—the level of judicial dissensus—plays an outsized role in journalists’ decision-making process. As they learn about a decision from the media, the American people draw upon the details included in news coverage of a decision, especially the amount of dissensus, to determine whether or not to accept a judicial decision and whether to update their views on the issue in question. Salamone’s major contribution is to articulate specific conditions under which the Court’s decisions are likely to be covered by the media and to persuade the public.

The book’s organization follows chronologically the chain of events that accompany a judicial decision. Following a review of the existing literature in Chapter 1, Chapter 2 reviews the evolution of dissensus on the U.S. Supreme Court and articulates three hypotheses that might characterize the relationship between dissensus and the public’s reaction to the decision. The “Marshall-Warren” hypothesis states that any dissent in a case could harm the Court’s public standing. The “Borah Hypothesis” suggests that the Court’s standing is only harmed through repeated 5–4 decisions. The “Procedural Representation” hypothesis suggests that dissent might actually be beneficial; by proving to the public that alternative arguments were heard and respected, the presence of dissent in a case could actually improve the Court’s public standing.

Chapter 3 provides the first of three sets of major empirical analyses. Based on coverage of the Supreme Court in the Chicago Tribune, Los Angeles Times, New York Times, and Washington Post from 2005 to 2013, Salamone tests the hypothesis that increased dissensus affects the probability that a decision is covered in the press. The analysis uses a unique dependent variable: the change in case salience (newspaper coverage) from before the decision to after the decision. He finds that as the amount of dissensus in a decided case increases, the amount of newspaper coverage it receives increases as well.

The focus on journalists’ decisions continues in Chapter 4, which analyzes the content of newspaper coverage of the Court. Salamone’s theory suggests that increased dissensus affects the likelihood that a journalist will frame a decision in ideological terms. The results support the theory. As dissensus increases, so do a) the likelihood that a decision is framed in ideological terms and b) the number of justices mentioned by name in the newspaper. Taken together, Chapters 3 and 4 provide a comprehensive—and much needed—account of the foundations of case salience, demonstrating convincingly that case salience and disagreement on the Court are thoroughly intertwined.

Chapter 5 moves the focus away from journalists to the American people. Salamone tests the three hypotheses set forth in Chapter 2 in a novel, nationally representative survey experiment. Respondents learned about three hypothetical Supreme Court decisions at varying levels of salience: gay rights (highly salient), employee privacy (moderate salience), and contract disputes (low salience). The level of dissensus among the justices was randomized for each decision, with some respondents learning of a unanimous decision, some learning of an 8–1 decision, others learning of a 5–4 decision, and a control group getting no information about dissensus. The dependent variables in the analysis are acceptance of the Court’s decision and agreement with the Court’s decision. The results defy easy explanation; generally, on high-salience issues, public opinion seems to be crystalized, and it is difficult for the Court to have much persuasive power; on lower-salience issues, the Court’s power is greater, and dissensus may sometimes increase support for the decision and foster opinion change. These results—which provide specific conditions under which the Court has the ability to affect public opinion—provide an important theoretical and empirical foundation for future work.

The book presents two obvious paths forward for those interested in understanding the Court’s persuasive role in American society. First, like much of the research on this topic, Salamone tends to conflate a case’s salience with its newspaper coverage. This enables him to use the level of dissensus in a case to predict the amount of news coverage a case receives. Future work should explore the potentially endogenous relationship between case salience and dissensus on the court: More salient cases may make justices more willing to pay the costs of writing a dissenting opinion (suggesting that salience causes dissensus on the Court). At the same time, the author’s findings suggest that dissensus drives changes in visible case salience. This relationship is ripe for experimental testing.

Second, future work needs to examine the generalizability of the conditions for persuasiveness that Salamone develops. Most notably, it is likely that survey respondents realized they were being deceived in the gay marriage decision since the survey was fielded before the Court’s final decision on that topic. On the less salient issues, it is less likely that respondents knew they were being deceived. As a result, the strength of the experimental treatment likely varies alongside the salience of the case, potentially confounding some of the relationships Salamone observes. Future work should examine the Court’s persuasive power across an even broader set of issue areas in order to cement our understanding of the Court’s ability to shape public opinion.

Perceptions of a Polarized Court represents an important advance in our understanding of the relationship between the Supreme Court and public opinion, by making prominent the role of media coverage as an intervening factor and illuminating the conditional effect of issue salience on the Court’s ability to affect public opinion. This book is a must-read for all who are interested in the role of the Supreme Court in the American political system and in American life more generally.