Legislative scholarship has long examined the relationship between individual members and the parties to which they belong. Kathryn Pearson’s new book sheds light on these intraparty dynamics in the U.S. House of Representatives from 1987–2012. Specifically, Pearson asks when and how Congressional party leaders reward their members for loyalty to the party. In addition to simply expanding data on party loyalty to the most recent Congresses, this impressive book carefully measures and examines different types of loyalty and party rewards. The theoretically motivated empirical analysis convincingly shows that party leaders use various strategies to reward and punish members depending upon the type and degree of loyalty that they show. As comparativists, we always admire the depth of knowledge and quality of data in U.S. Congressional research, and this book is exemplary with respect to both of these traits.

Pearson lays out her core theoretical argument in Chapter 2. She suggests that when enforcing party discipline, parties face a tension between maintaining control over a partisan policy agenda and seeking to gain or maintain majority control in the chamber (p. 36). Parties—and majority parties, in particular—have tools at their disposal to incentivize loyalty to the parties’ policy goals, but if leaders employ these tools too often (or demand too much loyalty) they may jeopardize the electoral chances of marginal members. These marginal members may benefit electorally by deviating from the party message. Pearson hypothesizes that “majority party leaders prioritizing policy control discipline their members more frequently than leaders pursuing majority control” (p. 37). She tests this core hypothesis in the three main empirical chapters of the book using a variety of data and measures.

After laying out the theoretical argument, Chapter 2 provides context for the analysis by offering historical detail and data on chamber margins, vulnerable incumbents, the changing policy agenda, and the nature of intraparty groups such as the Tea Party Republicans or the Blue Dog Democrats. Chapter 3 proceeds to describe the primary independent variables, namely various measures of party loyalty. These include roll call loyalty (particularly on procedural votes), signatures on discharge petitions, rhetorical party loyalty in one-minute speeches, and fundraising through member-to-member contributions. This diversity of measures is remarkable given that studies of the U.S. Congress have tended to narrowly focus on voting loyalty. By relying on measures from speech data and other variables, Party Discipline in the U.S. House of Representatives relates to recent comparative studies of party discipline that examine and account for selection bias found in legislative voting records.

Chapters 4 through 6 examine how loyalty and electoral vulnerability impact rewards from the party in terms of access to the legislative calendar (Chapter 4), desirable positions on committees (Chapter 5), and campaign funds (Chapter 6). Generally, Pearson finds that party leaders reward various types of loyalty when it comes to the legislative calendar and committee assignments, while campaign contributions are much more a function of electoral vulnerability. Leaders may rarely allow the worst party dissidents the chance to serve on the prestige committee of their choice, but leaders value that they were elected in the first place. Leaders are unwilling to jeopardize a seat by cutting off campaign funds to their party rebels. But even when it comes to the legislative calendar, there appears to be significant variation in how parties and leaders reward loyalty. For Democrats, with the exception of party fundraising, no measure of loyalty seems to matter for getting one’s bills considered on the floor. However, members who showed loyalty on votes (and specifically on procedural votes) were often more likely to have their resolutions brought to the floor. Even here, though, leaders in the 102^nd and 103^rd Congresses seemed to use resolutions as a mechanism to help vulnerable members as much as they did to reward loyalists (see pp. 88–92). These nuanced findings are indicative of the careful attention to detail found throughout the book.

Although primarily written for an American politics audience, Party Discipline is highly relevant for comparative legislative scholars. Comparativists have long acknowledged the impact of electoral rules on the behavior of party leaders, individual legislators, and parliamentary parties. By comparative standards, members of the U.S. Congress face a powerful incentive to cultivate a personal vote—that is, to appeal to the electorate on the basis of their individual legislative record. Compared with leaders in more party-centered electoral systems, U.S. party leaders ought to have fewer incentives to interfere with the activities of their members, even if the members and the party are ideologically at odds. Indeed, this dynamic may have been best reflected in the seniority norms of the “textbook Congress” period. Party Discipline shows how in recent years even in the U.S. context, majority leaders balance policy and majority control.

From a comparative perspective, one question that emerges from the book is why party leaders would ever develop ambitious partisan policy agendas in a system where such a focus may come at the detriment of the electoral fortunes of party members. The answer of Party Discipline is to treat party leaders’ policy ambition as an exogenous variable measured by coding key votes from CQ Weekly reports for indications that they were the result of party leaders’ policy agendas (pp. 44–45). This measure, however, not only reflects leaders’ policy ambitions, but also behavior. Majority party leaders may be selective in the votes they bring to the floor. Pearson hypothesizes that majority party leaders prioritize policy control when they pursue active partisan policy agendas and when chamber majorities are narrow (p. 37). But the causal pathways here are likely more complex. Narrow margins in the chamber may cause majority party leaders to both tamp down policy expectations and to pursue strategies aimed at preserving majority control.

Additionally, in Chapter 2 (and when setting out hypotheses in the later chapters), the argument tends to pit majority control against policy control. But Pearson herself acknowledges that these are not “mutually exclusive alternatives” (p. 78). To the extent that policy programs help parties win elections, there is no trade-off. In short, the theoretical relationships between chamber margins, policy agendas, and majority control are likely more complex than Pearson makes them out to be. A more precise distinction between leader policy ambition, its manifestation in legislative behavior, and the causes of both, may be a useful extension for future work both in the United States and comparative context.

A notable difference of the book with regard to the comparative literature on legislatures (e.g. Christopher Kam, Party Discipline and Parliamentary Politics, 2009) is that the dependent and independent variables are reversed. While the comparative literature treats loyalty (or more commonly, rebellion) as the dependent variable explained by party tools for sanctioning, Pearson’s theoretical approach posits the reverse causal relationship: Rewards and sanctions by the party leadership are largely dependent on the member’s previous party loyalty. This raises an interesting question: If members of Congress are aware of these reward and sanctioning patterns and care about committee transfers and campaign contributions, why do they not elicit higher discipline in the first place? From the “loyalty as dependent variable” perspective, the empirical findings would suggest that the reward and punishment mechanisms only work for a certain subset of members, namely those who disagree with the leadership but can be cajoled into compliance. In the conclusion, Pearson does examine whether those members who were rewarded in the previous Congress become more loyal in the next, and she finds only modest evidence of this (pp. 166–169). But of course, we would expect to observe no effect if the sanctioning mechanisms were working properly in equilibrium. At a minimum, the analysis suggests that both American and comparative scholars should pay closer attention to the likely reciprocal nature of these relationships.

Finally, one way the book’s appeal could be even further strengthened is to extend the theoretical focus beyond the majority party leadership to the minority party. Majority control has alternated several times between Democrats and Republicans during the period of investigation. Even though minority party leaders are unable to control the floor agenda and have fewer mechanisms for rewarding their members and passing their policy agenda, they nevertheless have an incentive to present a unified face on policy. While in their most general form, the book’s theories and hypotheses would hold for both majority and minority parties, the hypotheses with respect to majority control, in particular, tend to focus on how the majority party maintains control, rather than how a minority party might gain it. Thus, the book’s scope is largely (but certainly not entirely) limited to studying the majority party.

Party Discipline constitutes a major accomplishment in the study of party leader strategies and party discipline in the U.S. Congress. It is provides new insights into party behavior during this most recent period of increasing partisanship. We recommend it to all scholars of legislatures and parties, Americanists and comparativists alike.