I appreciate Sven-Oliver Proksch and Jonathan Slapin’s thoughtful and constructive review of Party Discipline in the U.S. House of Representatives. Their critiques show the value of incorporating comparativists’ insight into the study of the U.S. Congress, particularly in an era when parties are central to legislative organization and behavior and the number of cross-pressured members elected from districts that select a presidential candidate of the other party declines nearly every cycle.

Proksch and Slapin raise important questions about the measurement and significance of majority party leaders’ policy agendas. My measure only includes items that leaders actually brought to the floor and therefore misses other bills and other calculations that affect the floor agenda, including electoral considerations, the other bills under consideration, items’ likelihood of passage, Senate behavior, and the President’s position. A more in-depth theoretical and empirical study of party leaders’ policy agendas and their fate would benefit my research and the subfield more broadly.

Majority control and policy control are not exclusive, but it is difficult to know how much overlap there is, as leaders and members themselves face uncertainty about the electoral consequences of key votes. Proksch and Slapin argue above: “To the extent that policy programs help parties win elections, there is no trade-off.” Yet, the literature is mixed; scholars have shown that voting for President Clinton’s agenda in the 103^rd Congress and President Obama’s agenda in the 111^th Congress hurt Democrats in marginal districts, all else equal. In my interviews, leaders and staff indicated that passing legislative party priorities hurt vulnerable members, even as it was beneficial for the party to achieve legislative accomplishments.

Proksch and Slapin point out that from a comparative perspective, in which the dependent and independent variables are reversed, my empirical findings 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.” Indeed, there are many—often most—members who do not need incentives from party leaders to support the party when they cast roll call votes. That is why I incorporated district partisanship and seat safety into leaders’ calculations, and I also included other indicators of party loyalty, including party speeches and fundraising, that help members stand out to leaders beyond their loyal voting record.

I concur with Proksch and Slapin that my book would have been stronger with additional attention to the minority party, even as minority party leaders are positioned to pass their party policy agenda. Separate research by Matthew Green; Frances Lee; and John Pitney and William Connelly thoughtfully and thoroughly explains minority party behavior during this era, making clear that minority parties play an important role even in the absence of agenda control and that minority parties have evolved in their battle to gain influence in the majoritarian House of Representatives.

I look forward to continuing to gain insight from Proksch and Slapin, as well as other comparativists studying legislatures, and I urge my Americanist colleagues to do the same.