How an ideologically concentrated minority can trump a dispersed majority: Nonmedian voter results for plurality, run-off, and sequential elimination elections

In contrast to Downs' (1957) median voter result for two-candidate elections, we should not expect multicandidate elections to produce outcomes around the median, even on average. Rather the winning candidate will tend to be between the median voter and the mode. This is true whether we consider plurality, run-off, or sequential elimination elections, and whether or not the electorate is divided into factions that control the nomination of candidates.

For an unfactionalized electorate, computer simulation with randomly positioned candidates is used to model various electoral systems. This is because no equilibrium solution exists for this case. For a factionalized electorate, a game-theoretic model of faction formation is used.

The results suggest that an ideologically cohesive minority around the mode of the population distribution may have a disproportionate influence on the outcome. These results can be applied to party leadership in the U.S. House, following Grofman, Koetzle, and McGann (forthcoming).