Nate Silver explains why:
That Mr. Obama won the presidency by a relatively narrow margin this year and that Democrats do not control the House would argue against a wave election this year. Still, the more likely situation is losses rather than gains for Democrats, based on the historical record. And a 17-seat gain would strongly defy historical precedent.
Nor did Democrats come especially close to winning the House in 2012, once one examines the results from individual races more carefully.
This year, there were only 11 House seats that Democrats lost by five or fewer percentage points. Thus, even if they had performed five points better across the board, they would still have come up six seats short of controlling the chamber.
In other words, Democrats would have to perform quite a bit better in House races in 2014 than they did in 2012 to win control of the chamber – when usually the president’s party does quite a bit worse instead.
One should never say never when it comes to forecasting the outcome of an election two years in advance. But it might take a major scandal in the Republican party, or for Republicans to splinter into factions, for Democrats to have more than a remote chance of winning the House.
And there is one more factor working against Democrats: they have become increasingly reliant upon voters, like Hispanics and those under the age of 30, who do not turn out reliably in midterm election years. Democrats have a broader coalition than Republicans do in high-turnout environments, so perhaps this will benefit them in 2016. But these are not the voters you would want to depend upon to make gains in midterm election years, when turnout is much lower.
Also of concern to the Democrats is the fact that the list of Senators up for re-election in 2014 includes seven Senators in states that Mitt Romney won this year and one in a swing state, Virginia, that may end up being vacant if Mark Warner decides to run for Governor next year as many here in the Commonwealth believe he might. By contrast, all of the Republican Senators up for re-election but one, Susan Collins, running in a solid red state. If history is any guide, the incumbent President’s party is likely to lose seats in Congress in 2014 rather than gain them.
