Abstract Over the last several decades, the onset of political nationalization, party polarization, and negative partisanship have shifted the motivations, strategies, and tactics of those who financially participate in congressional elections. These shifts have taken place amidst landmark campaign finance policy changes. In this paper, we use transaction-level datasets of individual campaign donations, independent expenditures, and political action committee donations from 1990 to 2024 to track these changes in congressional elections. Specifically, we argue that individual donors; party organizations; and non-party groups have reacted in divergent ways that match their electoral motivations and goals, and reveal important trends in American politics. For example, an analysis of the top House fundraisers and most competitive districts demonstrates how nationalization and negative partisanship are driving many individuals’ donations. Meanwhile, parties and ideological groups appear laser-focused on the most competitive races; while business and labor organizations continue to target safer incumbents with access-oriented giving and spending. A multivariate case study of the 2024 congressional elections confirms these suspicions, and highlights in particular the largely “wasted” millions of dollars donated by individuals to nationally-known partisan heroes and villains in non-competitive seats.
Hunt et al. (2026) studied this question.