The Changing Nature of Congressional Party Support in a Hyper-Partisan Era

Conventional wisdom suggests that many members of Congress face competing demands from their party and constituents, and therefore adjust their support for party positions as elections approach. Party leaders help members by avoiding the consideration of divisive votes when elections are near. Throughout much of the late 20th century, this dynamic produced a predictable election cycle effect in the U.S. House—a saw-toothed pattern in the frequency of party votes. However, that pattern was disrupted in the 1990s and has been unstable since. Our working hypothesis is that changes in the electoral and legislative arenas have mutually altered incentives surrounding members’ party support and the timing of divisive partisan votes. This study explores whether members have adopted a more stable, enduring support for party in recent decades, and whether there is less avoidance of divisive partisan votes in the lead-up to elections. We further examine the correlates of these behavioral changes, including the role of cohort replacement, electoral vulnerability, party size, party status, and calendar changes in the consideration of appropriations votes.