The party whips are essential components of the U.S. legislative system, responsible for marshalling party votes and keeping House and Senate party members in line. In The Whips, C. Lawrence Evans offers a comprehensive exploration of coalition building and legislative strategy in the U.S. House and Senate, ranging from the relatively bipartisan, committee-dominated chambers of the 1950s to the highly polarized congresses of the 2000s. In addition to roll call votes and personal interviews with lawmakers and staff, Evans examines the personal papers of dozens of former leaders of the House and Senate, especially former whips. These records allowed Evans to create a database of nearly 1,500 internal leadership polls on hundreds of significant bills across five decades of recent congressional history.

The result is a rich and sweeping understanding of congressional party leaders at work. Since the whips provide valuable political intelligence, they are essential to understanding how coalitions are forged and deals are made on Capitol Hill.

In Why Americans Split Their Tickets, Barry C. Burden and David C. Kimball argue that divided government is produced unintentionally. Using a new quantitative method to analyze voting in presidential, House, and Senate elections from 1952 to 1996, they reject the dominant explanation for divided government, that ticket splitting is done to balance parties that are far from the center. The ideological positions of candidates do not matter in American elections, but voters favor centrist candidates rather than a mix of extremists. When candidates of opposing parties adopt similar platforms, ticket splitting arises. For voters, ideological differences between the parties blur and other considerations such as candidate characteristics exert a greater influence on their voting decisions. Among their other findings, the authors link changes in congressional campaigns--namely the rise of incumbency advantage and the greater importance of money in the 1960s and 1970s--to ticket splitting and argue, in addition, that the transformation of the South from a Democratic stronghold to a Republican-leaning environment has made regional factors less important.

Burden and Kimball draw upon a diverse and unique range of data as evidence for their argument. Their analyses rely on survey data, aggregate election returns, and new ecological inference estimates for every House and Senate election from 1952 to 1996. This approach allows for the examination of divided voting in traditional ways, such as choosing a Democratic presidential candidate and a Republican House candidate on a single ballot, to less traditional forms, such as voting in a midterm House election and choosing a state's Senate delegation.

Barry C. Burden is Assistant Professor of Government, Harvard University. David C. Kimball is Assistant Professor of Political Science, University of Missouri, St. Louis.