Incumbency Disadvantage in U.S. National Politics: The Role of Policy Inertia and Prospective Voting

Abstract

We document that postwar U.S. national elections show a strong pattern of "incumbency disadvantage": If the presidency has been held by a party for some time, that party tends to lose seats in Congress. We develop a model of partisan politics with policy inertia and prospective voting to explain this finding. Positive and normative implications of the model are explored.