Daniel Larison thinks that the GOP is only going to pick up 35 seats in the House - he lists them here - fewer than needed for a majority:
Gaining 35 seats in the House is impressive, and it will be the second-largest turnover in my lifetime, but after the overhyping of Republican chances for the last year it will seem anticlimactic and unsatisfying. The reality that gaining 35 won’t be enough to win a majority serves as a reminder just how far down the GOP had sunk in the last four years, which should remind us that the GOP deserved to be so far down. It should also make us realize the gains the GOP makes this year are largely unmerited. Right now, everyone in the “biggest tent” is working together and setting aside disagreements for the sake of winning the election. What happens if Republicans don’t win? The round of post-election recriminations will be that much more severe and bitter when it becomes clear that the party failed to take advantage of one of the most favorable election years in decades.
If Republicans do manage to eke out a House majority, the electorate won’t have provided them with even the illusion of a mandate, and their leaders have already made clear they have no desire for fiscal responsibility. Riding an entirely negative electoral wave created by a weak economy, Republicans will see that they have not have been elected for any particular reason. They will devolve into their usual time-serving habits even faster than before.