Pulling back just a bit, I feel like the long-term implications of Republicans winning the Massachusetts Senate seat have been oversold. The short term-implications -- creating the real potential to kill health care reform for another generation -- are real. But people are getting carried away with what it means about the political environment. I'm talking about sentiment like it's so shocking that a Republican could win "even in this bluest of states," or that "The fact that it's even close is stunning. If [Brown] actually wins, it will be one of the greatest upsets in modern times."
It's not actually that uncommon for a Senator to win an election in a state that tends to heavily favor the opposite party. These kinds of wins happen when you have an open seat and a talented challenger who effectively distances himself from the national party. Scott Brown, a former Cosmo nude model who touts his old pickup truck and incessantly vows to be an "independent voice," is a really strong candidate. Martha Coakley, who's a poor politician and prone to terrible gaffes, is not.
It helps for such a candidate to have a political wind at his back, but it isn't necessary. Ben Nelson won in Nebraska in 2000, and Nebraska is as Republican as Massachusetts is Democratic. (In 2000 -- a good test because it was an almost-even election -- Nebraska gave George W. Bush 58.9% of the vote, while Massachusetts gave Al Gore 59.9%.) Nelson's election did not mean there was a pro-Democratic earthquake that made every Republican vulnerable. He was an attractive politician who ran a good race, though "attractive" in some way that may be peculiar to Nebraskans.
Now, as it happens, the Democrats certainly are going to get shellacked in 2010. The Democrats are the party in power and they're going to bear the political brunt of a midterm election and 10% unemployment. But President Obama remains fairly popular, and the Democratic party is still more trusted than the GOP. The results of one race are hardly some freakish harbinger of a total political sea change, Democrats prone to be losing everywhere, a country veering wildly right.