The Electoral Consequences of Party Switching by Incumbent Members of Congress, 1947–2000

What are the electoral consequences of switching parties for incumbent members of Congress? Do incumbents who switch fare better or worse after their switch? Aldrich (1995) and Aldrich and Bianco (1992) present a model of party affiliation for all candidates. We empirically extend this model for incumbent legislators who have switched parties. Specifically, we look at the universe of incumbent representatives who have run for Congress under more than one party label since World War II. We find that the primary and general election vote shares for party switchers are not as high after the switch as before. Additionally, we learn that party switching causes the primaries in the switcher's party and in the the opposing party (the switcher's “old” party) to become more competitive in the short run. Over the long run, however, primaries in the switcher's new party are less competitive than those in the old party before the switch.