UNCONTESTED SEATS AND ELECTORAL COMPETITION FOR THE US HOUSE-OF-REPRESENTATIVES OVER TIME

We examine how changes in the incidence of uncontested seats for the U .S. House of Representatives over time reflect responses to partisan c hange, changes in electoral rules, and long-term secular changes in th e American political system. We use a multiple interrupted times serie s model to test the relationship between the number of uncontested Hou se seats from 1912 to 1994 and the 1932 realignment, midterm elections , the rise of the Republican South, redistricting, the abolition of cr oss-filing laws in California, and the pronounced rise of the incumben cy advantage since 1966. We test models explaining the number of uncon tested House seats occupied by each party and the difference between t he parties in the number of those seats. We find that the rise of the Republican South started in 1964 and the incidence of midterm election s contributed strongly to changes in the overall rate of uncontested H ouse races.