The Nationalization of Individual Campaign Contributions in U.S. Senate Elections, 1984-2020

This article explores the trend of increasing nationalization in American politics and its effect on the U.S. Senate's federalizing dynamics, using campaign finance as an indicator. We analyze the geographic distribution of campaign contributions to U.S. Senate races from 1984 to 2020, tracing the nationalization of donor behavior in America. Key findings suggest that more ideologically conservative senators and those running for their first election are likely to rely heavily on out-of-state donations, with regional differences also evident. We argue that the nationalization of campaign finance challenges the Senate's representative structure and hints at another dimension of inequality in American politics—geographical versus national influence. This study offers no definitive normative argument but posits restricting out-of-state donations as a potential solution to address the growing inequality in the voting power of Senate members.