Anti-incumbent Motivations in Presidential vs. Midterm Elections

One thing that’s been a consistent theme in talk about the presidential election next year is that the main motivator for Republican voters seems to be dislike of Obama, rather than enthusiasm about any of the GOP candidates. And today, Newt Gingrich predicted big GOP pick-ups in the House and Senate again next year. Which got me wondering: we know that anti-incumbent moods can swing a midterm election, but does the same hold for congressional races in presidential election years?

My intuition is to say no. Since midterms have much lower turnout on average, a strong anti-incumbent mood among out-party voters can provide a strong motivation in otherwise uninspiring races (i.e., when few voters have strong feelings about the individual candidates). This could thus sharply skew the relative turnout between each party’s base in a midterm. In presidential years, though, the presidential contest provides a positive motivation for in-party voters to turn out; if out-party voters have only a negative motivation (voting against the incumbent, but not necessarily for their nominee), the relative turnout difference should be much smaller.

(Note that I’m assuming overall preferences are held constant; in other words, that voters aren’t changing their minds about whom to vote for, they only choose whether or not to show up/donate/mobilize others and so forth.)

But this is just a conjecture, and I’m sure somebody’s already studied it. If so, can anyone recommend some reading on this topic? I’ve got some original survey data on the strength of each candidate’s coattails in 2008, and am thinking of combining that data with a broader study of the effects of presidential candidates on congressional races. As such, any suggestions about where to start re: previous work would be put to good use.

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