Incumbency Advantage and the Persistence of Legislative Majorities

Abstract

Between 1955 and 1995, although the GOP occasionally controlled the Senate and won landslide presidential election victories, the Democratic party controlled the majority of seats in the U.S. House. This paper argues that Republican, indeed, any minority party's problems stem from the interaction between career decisions and electoral prospects. We argue that there is a previously overlooked link between the incumbency advantage and the long-term persistence of legislative majorities. We develop a model that shows how the incumbency advantage can produce higher retirement rates among the minority party, which in turn decreases the likelihood that the minority party will win a majority of seats in the next election. Data on actual retirement rates of members of the U.S. House and of the U.K. Parliament fit the patterns predicted by our model.