Incumbent Vulnerability and Challenger Entry in Statewide Elections

Abstract

Prior studies of challenger entry in Senate and gubernatorial elections provide inconclusive evidence that challengers consider incumbents' electoral vulnerability when deciding whether to run. The reason for this is primarily methodological: These studies analyze only general-election challengers, and in so doing overlook the dominant share of candidates who enter races. Additionally, the manner in which incumbent vulnerability affects challenger entry varies with the challenger's party status and electoral strength. Incumbent-party challengers run against incumbents who did poorly in the previous primary election, whereas out-party challengers run against incumbents who did poorly in the previous general election. Finally, the entry decisions of weak out-party challengers are not directly related to incumbent vulnerability; rather, they avoid facing strong out-party challengers in the primary election. These hypotheses are tested using data from Senate and gubernatorial elections from 1976 to 1998; the hypotheses are supported.