Andrew Kohut is founding director of the Pew Research Center.

By this point in the campaign season, the projected outcome of the midterm elections has been hashed and rehashed and even inspired some wonk-on-wonk fights along the way. The conventional wisdom is that 2014 is a Republican year—the GOP will keep the House and may well win the Senate. But surprisingly, as the elections approaches, the latest round of polling suggests that Republicans might not do as well in the popular vote for the House as expected. And that, in turn, means there might not be enough of a GOP tide to give Republicans an edge in the key Senate races they need to win a majority of seats in the upper chamber.

Consider the 2010 midterms, when a wave of Tea Partiers helped Republicans retake the House. That year, the GOP won the popular vote by 7 percentage points. The latest Pew Research Center survey, by contrast, finds only a 3-point GOP advantage in this year’s midterms: 47 percent of likely voters report intending to cast a ballot for a Republican candidate, versus 44 percent for a Democrat. And these results are not outliers, nearly matching six Real Clear Politics surveys taken in early September.


So this time around, will Republicans in the House pick up fewer seats than we expect? The Pew survey identifies two important measures that offer clues: which party is more popular among all voters and which party’s supporters are most likely to turn out on Election Day.

While the Democrats have a significant lead on the former count, the Republicans lead on the latter—but not as decisively as they did four years ago. The Democrats hold a 5 percentage point lead among all registered voters: 47 percent of respondents preferred Democrats in Pew’s early September survey, compared with 42 percent who favored Republicans. But Republicans, importantly, hold as big a turnout advantage as they did in 2010, accounting for the GOP’s modest 47 percent to 44 percent margin among likely voters this year.

In 2010, by comparison, the two parties were about equally popular among all registered voters, according to Pew, but Republicans were also much more motivated to cast ballots. In 2006, Republican supporters were more likely to vote, but the Democrats were the much more popular party, to such an extent that they won the popular vote by a margin of 4 percentage points.

The question mark now, looking toward November, is turnout, not the relative popularity of the two parties. Ever since the debt-ceiling crisis in 2011, the GOP’s favorable ratings have trailed the Democratic Party’s— 37 to 46 percent in Pew’s last comparison. It is unlikely that this will change materially in the next month and a half, given that the Pew survey found only a modest number of potential swing voters: Just 3 percent of Republican and 3 percent of Democratic supporters said they were only leaning to the party of their choice and still might change their minds on Election Day.

As for turnout, the Democrats have a high hill to climb. Republicans are more engaged, more enthusiastic about voting and more optimistic about the outcome of the election—as they have been for most of the year. Democrats, in contrast, are in a funk. They have given the election a lot less thought, they are pessimistic about the party’s chances and fewer are certain that they will cast a ballot in November. In a late August Pew poll, 61 percent of Republican and “GOP-leaning” registered voters believed their party would do better this year compared with other recent elections—roughly double the 32 percent of Democrats who felt the same about their own party’s chances.

So can Democrats replicate a late surge in turnout, as they did in 2012, to make House races more competitive and pick up more seats? Pew results from the last two congressional elections suggest probably not. The turnout spreads between the parties changed hardly at all between early September and election time in recent Congressional elections.

Even so, the GOP’s relatively thin 47-44 lead in the current polls also strongly suggests that this is not a tide election—which could affect the heated battle for control of the Senate in a handful of key states. If the GOP is to regain control of the Senate, it will have to be on the strength of its Senate candidates, not on the coattails of a decidedly pro-Republican national mood.