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The year after Barack Obama’s reelection was a roller coaster ride for both parties. Obama won convincingly but soon saw his approval rating slip amid controversy over the Internal Revenue Service’s scrutiny of Tea Party groups. Then the government shutdown last October was widely perceived as damaging the Republican Party’s brand and its prospects in the 2014 midterm election. How likely is this to prove true?

The American National Election Studies have been asking Americans to evaluate the Democratic and Republican parties for almost fifty years (since 2000, only in presidential election years). Respondents evaluate each party positively or negatively on a “feeling thermometer” that ranges from a chilly zero degrees to a toasty one hundred. Comparing these assessments to the popular vote in House elections shows that the more positively one party is evaluated relative to the other, the more of the House vote it tends to win. In the fall of 2012, Americans, on average, rated the Democratic Party at fifty-five degrees and the Republican Party at forty-seven, and, indeed, Democrats won the popular vote for the House that year.

What does this mean for 2014? In a late October YouGov poll, respondents rated the parties on similar feeling thermometers. Although this poll occurred just after the shutdown, respondents gave the Democratic Party the same eight-point advantage that it had in 2012. If that does not change between now and the election, party brands alone suggest the Democrats would win 54 percent of the House popular vote—as they did in 2006 when they retook the House.

But there are three reasons Democrats should not be too optimistic. For one, despite an eight-point-better party brand in 2012, they won only 51 percent of the House popular vote and lost the chamber. This could reflect the traditional advantages of incumbents, who tend to outperform their party’s expectations. Many Republican incumbents ran in 2012.  

Second, votes do not always translate into seats. In elections since 1994, including 2012, the GOP has generally won more seats than their vote share and thermometer reading would lead one to expect. Redistricting has some effect on this, but less than many commentators believe. A big part of the reason Republicans won more seats than votes in 2012 was that incumbency advantage, which helped candidates who would otherwise have lost retain their seats by small margins. Democrats also waste their influence because their votes are concentrated in urban areas.

Finally, the shutdown may not be salient to voters come Election Day. The reopening of the government allowed Washington to turn its attention to the rocky rollout of Obamacare. Meanwhile, Obama’s approval rating has declined further, creating headwinds for Democratic candidates. Taken together, these factors suggest that, for both parties, gains and losses in the midterm will be small. And that means more of the slow grind of divided government.