One of the great fears politicians have is that there will be some wave of strong feeling among the public that they will be oblivious to, until it rolls over them and it's too late to do anything about it. This happened to Democrats in 1994, and it happened to Republicans in 2006. Right now, a lot of Democrats are worried that there's another wave of strong feeling coming at them. Republicans have been working very hard to convince them that the teabaggers screaming about socialism represent more than a small minority of the country (they don't), and that the current voter discontentment doesn't really have much to do with the economy – which would mean that your average independent voter will still be determined to throw the bums out even after the economy recovers.
Progressives often observe that the news media let Republicans get away with things they never let Democrats get away with, and that's often true. But we also have to acknowledge that how controversial a particular action becomes has a lot do with the choices that political actors make. Republicans are very, very good at ginning up controversy over something a Democrat said or did. Democrats could do the same thing, if they put their hearts into it.
But much of the time, they just don't. Which is why we get things like this:
This is what I'd like to hear a congressional Democrat say:
"We're obviously disappointed about the results of the special election in Massachusetts. But the fact that we have gone from a 20-seat advantage in the Senate to an 18-seat advantage in the Senate doesn't mean that Republicans are in charge. They had eight years under George W. Bush to push their agenda, and they pushed it good and hard. There's a reason that at the end of that eight years, the voters elected Democrats to the White House and large majorities in Congress. That hasn't changed.
It's entirely possible that by the end of the night, Martha Coakley will have squeaked by with a win in the Massachusetts special election, and all this sturm und drang will have been for nothing. But if that doesn't happen, Republicans are gearing up to tell us that this one election in one state is The Most Important Thing That Has Ever Happened, and one that means more than, say, the elections in which the country gave Democrats the White House and large majorities in both the House and Senate.