Do Quality Candidates and Incumbents Still Matter in the Partisan World? Comparing Trends and Relationship Between Candidate Differentials and Congressional Election Outcomes, 1900–2022

Abstract

The increase in elite-level polarization and the changing partisan nature of elections to the U.S. House led scholars to posit that candidate characteristics are minor considerations in determining these election outcomes. However, it is not clear if these trends extend to the U.S. Senate or if candidate considerations have lost the relatively minor predictive power they exhibited during the 2010s, particularly as partisanship continued to rise as a predictor of election outcomes. Using historical data on elections to the U.S. House and Senate from 1900 to the recent 2022 midterm elections, we test whether the incumbency advantage and candidate quality differentials are still salient predictors of congressional elections. We find that the incumbency advantage largely disappeared as a salient component of election outcomes for both chambers as partisanship increasingly shapes these outcomes. By contrast, we find that candidate quality differentials, while waning, still can play a considerable role in shaping congressional election outcomes, particularly in the Senate. We conclude by showing that the declining emergence of quality candidates may have played a pivotal role during the 2022 election cycle by costing Republicans control of the U.S. Senate.