The Republicans are behaving like they don’t think they have any chance of beating President Obama and are throwing most of their energy into retaking the U.S. Senate. Of course, the two things are related. In order to take back the Senate, the Republicans need a presidential candidate who can at least hold their own in traditionally red states. If you take a look at the Senate races in 2012, you’ll notice that the Republicans are very fortunate. They are defending seats in Mississippi, Utah, and Wyoming, for example. Those states might even vote for Michelle Bachmann over President Obama. The Democrats are hoping to beat Scott Brown in Massachusetts and Dean Heller in Nevada. Beyond that, they have an opportunity to win an open seat in Arizona and then they have to hope that Richard Lugar and/or Olympia Snowe get beaten in a primary, opening up their seats for potential pickups. And there’s Texas, I guess, if the presidential election gets really lopsided.
The Republicans have tons of targets and they only need to net four seats to take control of the Senate (three, if the win the presidency). So, basically, the Republicans should be able to win the Senate even if they lose the House and get crushed in the presidential contest. But nothing is guaranteed if their nominee is a joke that can’t even compete for 40% of the vote.