Do the Advantages of Incumbency Advantage Incumbents?

We develop a model that calls into question whether some key sources of incumbency advantage frequently cited in the empirical and theoretical literature are, in fact, beneficial to all types of incumbents. Our results show that increases in direct officeholder benefits, such as the “campaign discount” that incumbents enjoy relative to challengers and the pro-incumbent bias of interest groups making endorsements, as well as increases in district partisan bias favoring the officeholder, encourage pooling among incumbents of higher and lower quality in equilibrium. While this means an improvement in the electoral prospects of lower-quality incumbents, it is harmful to those of higher quality. Whether the net electoral consequence for high-quality incumbents is positive or negative depends on whether the pooling effect is direct or mediated through voters’ choices. Our findings suggest, further, that fundamental tensions may exist between accounts of incumbency advantage focusing on the sources noted above and on selection through repeated elections and challenger scareoff. They also point to obstacles to disaggregating the sources of incumbency advantage empirically.