The Polls: Presidential Referendum Effects in the 2006 Midterm Elections

Many commentators saw the 2006 midterm elections as a referendum on George W. Bush's presidency, especially his unpopular Iraq War policy. Presidential referendum effects may be highly likely given the degree of party polarization and the concomitant attachment of large numbers of voters to the Democratic and Republican parties. But local factors, especially incumbency effects, may also have affected the outcome of the 2006 midterm contests. Using state-level presidential approval polls, analysis finds that Bush's approval, an indicator of referendum voting, had little impact on voting in Senate contests, once applying controls for the ideological and partisan composition of state voting populations. In contrast, even with these controls, Bush's approval influenced voting in gubernatorial contests. But Iraq War battle deaths affected voting for senators, suggestive of another type of referendum effect. Battle deaths, however, did not affect the gubernatorial races.