Censure and Impeachment

You may have noticed that the Republicans are trying to make a really big thing out of the danger that if Democrats win the House and/or the Senate, they will try to impeach or censure the president. They seem to believe people will vote Republican to head off this eventuality. And, even the inside the beltway Democrats seem to be frightened by this strategy, apparently fearing that people will desert the Dems in droves if they fear the Dems will try to impeach or censure Bush. Why? Look at Bush's current approval ratings. He's in the tank, and sinking, while several spigots are wide open still filling it with water. My best guess is that by now a plurality of the electorate would welcome censure or impeachment if presented in the proper light.

Perhaps the Thuglicans are just trying to stir up their base with this stuff, but why the Democrats?