PIPE Workshop: Clémence Tricaud (UCLA Anderson)

Are US election outcomes historically close? This paper analyzes long run trends in elec- tion vote margins and party seat margins and links them to changes in the nature of political competition. We assemble a comprehensive database of historical electoral results for the US House, Senate and presidential contests, from the 19th century until today. Seat margins de- clined in the recent period, so the margins of control of the House, Senate, and Electoral College by either party have become smaller. However, this was not accompanied by a decline in the margins of victory at the constituency level. We interpret these facts in the context of a simple model of electoral competition with multiple districts. We show theoretically that the increase in politicians’ information about voter preferences, together with the growing nationalization of politics, can explain the decrease in seat margins and the concurrent stability in vote mar- gins. As implied by the model, we document that campaign contributions received by House candidates are increasingly concentrated in a dwindling set of swing districts.

Host or Publisher PIPE Collaborative