Median voter
Definition
The median voter is the voter positioned exactly in the middle of the political spectrum on an issue, with half of voters wanting more and half wanting less. The median voter theorem predicts that under majority rule, candidates converge toward this voter's preference to win elections.
Why it matters
The theorem assumes voters turn out equally and candidates compete honestly on a single dimension, but neither holds perfectly in practice, so real elections can be captured by whichever narrower group actually shows up or funds the race, shifting outcomes away from the true middle. Understanding the concept helps explain why safe, low-competition districts, where the effective median is far from the state's overall median, produce more extreme legislators than competitive ones.
Seen in the wild
Political scientists frequently cite the theorem to explain why U.S. presidential candidates in competitive general elections tend to moderate their platforms compared to primary season, when the relevant median voter is a partisan primary electorate rather than the general public.