I'm not incredibly surprised by Republican Scott Brown's defeat of Democrat Martha Coakley in yesterday's Senate election in Massachusett(e)s. Despite the fact that we're talking about perhaps the most solidly Democratic state in the Union, there were a number of reasons for this upset:
1) Scott Brown campaigned tirelessly from day one, while Coakley sat back on her 30 point lead for several months until she was shocked into action by recent polls showing that lead evaporating.
2) The closing of the margin had the effect of generating national attention, bringing money in from around the country which erased Coakley's fundraising advantage.
3) Any way you cut it, Coakley was not a good retail campaigner. She avoided the stump, and dismissed the idea of "shaking hands in the cold outside Fenway Park". She also forgot that Curt Schilling was a Red Sox hero, which is sacrilege to the blue collar Bostonians that the Democrats need to count on.
4) The expectation that the Senate seat was "the Kennedy seat" actually worked against the Democrats. First, it implied some sort of entitlement, and swing voters don't like being told that anyone or any party is "entitled" to a political office. At the same time, Coakley wasn't actually a Kennedy so the affection that a lot of Massholes had for the Kennedys didn't draw them to vote for her.
5) Coakley had some late breaking scandals, particularly a sex abuse case involing the Amiraults family.
6) Coakley's campaign had gone very negative in the closing weeks, which likely turned off a lot of voters. (Arguing that your opponent would turn away rape victims at hospitals is one of those charges that is a little too far fetched to be believable.) She'd have been better off toning that down, or at least using the negative attacks much earlier in the campaign when it might have given the voters a first impression of Brown.
7) The health care bill has become a complete disaster at this point, uniting the right and now having a number of prominent liberals (including Dennis Kucinich and Howard Dean) wanting to kill the beast. While voters correctly don't see an election of Scott Brown as advancing a GOP agenda--after all, even now the GOP only has 41 Senators--they did see him as a last hope of derailing a bill that is likely to be a total turkey.
8) Finally, the economy--let's face it, at over 10% unemployment (not to mention the fact that this number greatly undercounts the underemployed and those who have given up looking for work) the economy is in the crapper. Any time the economy is doing that poorly, incumbent parties are going to suffer, particularly if they're not seen as fixing the problem. A year after the stimulus package was passed, voters are sending a clear message and the "in" party--the Democrats--would be wise to take notice. What they can actually do about this, on the other hand, is anyone's guess.
All in all, it was a bad move in hindsight for Obama to go to Massachusetts to campaign for Coakley. It helped nationalize the campaign, and makes the election more identified with him and his policies. Expect plenty of spin in the next few weeks.