Abstract
Existing literature suggests that, if anything, larger constituencies make reelection more challenging for legislative incumbents. Yet theoretical arguments commonly are unclear about why more populous constituencies should disadvantage incumbents relative to challengers. Additionally, most empirical research has focused on congressional races, none of which involve small populations. I argue that there is good reason to believe that smaller size enhances challenger viability and thereby lowers incumbent safety. I also provide an empirical analysis of the relationship between constituency size and incumbent safety, focusing on individual contests featuring an enormous variance in district population and other research advantages: races for positions as California county supervisors. Controlling for both candidate and demographic variables, and examining both likelihood of winning and incumbent vote percentage, I find that there is a modest but consistent positive relationship between constituency size and incumbent safety.