Dynamics of Partisan Competition for Legislative Majorities in the U.S. House & Senate, 1959–2020

Abstract

What drives partisan competition over the pursuit of legislative majorities in contemporary congressional elections? While conventional wisdom suggests that the chances of a legislative majority is largely predicated on the public’s ideological policy preferences or national standing of the president, there is little work assessing the dynamics of partisan competition over the course of the electoral cycle. Leveraging over 60 years of new generic congressional ballot data measuring the monthly preference of the mass public’s partisan presence for the congressional majority, this paper finds that partisan competition for the majority largely centers on the national policy mood and the public perception of presidential performance rather than partisan conflict. This paper validates the importance of these findings relating to partisan competition for the legislative majority by showing that this electoral competition plays a significant role in predicting the national normal popular vote and partisan seat turnover from 1960 to 2020.