A voter-centric explanation of the success of ideological candidates for the U.S. house

In recent years, ideological candidates for the U.S. House have become increasingly successful, to the point where their chances of being elected are indistinguishable from moderates. However, scholars have still not uncovered exactly why this is happening. Using survey data from the American National Election Studies, I find that voter-centric explanations of vote choice – a voter's partisanship, ideology, and presidential approval rating – have increasingly predicted their vote choice in U.S. House elections from 1980 to 2016. Using data on candidate ideology, I find that candidate ideology is an increasingly poor predictor of individual vote choice over time. Original experimental data supports these claims, finding only a small electoral advantage for moderates, compared to ideologues of their own party, and evidence suggesting that, at least among Democrats, ideological candidates are rated more favorably than moderates. Taken together, these results suggest that the increased electoral success of ideological candidates can be attributed to changes in voters' decision calculus, rather than structural or candidate-centric explanations.