Six Explanations for Why Coakley Lost in Mass.

So whose fault is it? As Democrats pick up the pieces from their shocking loss in the Massachusetts Senate special election that is the question on the minds of Democratic strategists, who will be scrambling to try to prevent a similar result in November's congressional races. With the train wreck becoming apparent days in advance, theories have been flying for how State Sen. Scott Brown beat State Attorney General Martha Coakley, especially among the punditocracy. There are recriminations flying everywhere—Politico had an excellent roundup Tuesday—but here are a few of the prevailing ideas.

1. Martha Coakley is just a really, really terrible candidate. How do you lose Teddy Kennedy's seat in one of the most reliably blue states in the union? Some commentators say you don't try, you fail to know who Red Sox hero Curt Schilling is and you alienate voters.

Proponents: Jonathan Alter, Howard Fineman, Jason Zengerle, Josh Marshall, Ezra Klein, Markos "Kos" Moulitsas, Nate Silver, Karen Tumulty—even Jacob Weisberg wouldn't vote for her. And leading Democrats, including Sen. Bob Menendez, head of the Democratic Senatorial Campaign Committee, and supposedly Rahm Emanuel, are pushing this explanation, too.

Prime example: "Not since Grady Little gave away the American League pennant to the Yankees in 2003 has New England witnessed this level of ineptitude. Actually, that Red Sox reference would probably sail right over Coakley's head, when you consider that just the other day she told a gobsmacked radio host that Curt Schilling—who's endorsed her GOP opponent, Scott Brown—was a 'Yankee fan.' It was just the latest in a series of blunders that have helped Coakley blow a 30-point lead over Brown." —Zengerle, writing for New York’s Daily Intel blog

Is It True? It's hard to argue against. Even with an energized and resurgent right-wing base, this race should have been out of reach for Republicans. The only question is whether that's the only factor, or if there's more blame to go around.

2. Democrats took victory for granted. It's a variation on the charge that Coakley was too complacent early on: Obama and the Democratic Party didn't even bother until it was far too late.

Proponents: Daily Kos (again), E. J. Dionne, Jonathan Chait, Fineman (again) The executive director of the DSCC also admits that the national party could have done better. Unsurprisingly, the embattled Coakley camp is peddling this narrative, trying to shift the blame.

Prime Example: "Coakley campaign noted concerns about 'apathy' and failure of national Democrats to contribute early in December. Coakley campaign noted fundraising concerns throughout December and requested national Democratic help. DNC and other Dem organizations did not engage until the week before the election, much too late to aid Coakley operation." —Coakley campaign memo, via Politico

Is It True? Earlier national involvement might have helped, not to mention avoiding the weird spectacle of Obama feinting at staying away, then scheduling a last-minute trip to the Bay State that failed to turn the election. But even the theory's proponents—outside of Coakley's campaign—admit this factor only comes into play because of the candidate's failure.

3. Obama and liberals have been too aggressive; voters are alienated. The Democratic regime in Washington has just pushed too hard, too far left, and voters are responding to that.

Proponents: Matt Bennett of Third Way, Jonathan Capehart

Prime Example: "[It] shows that moderates are unhappy with the direction of the country. Moderates are uneasy, angry, nervous. [It may be a] wake-up call to Democrats." —Bennett, speaking to Reuters

Is It True? Probably, at least in part. The fierce opposition to Obama's agenda has driven a right-wing resurgence nationwide, and a poll from Suffolk University last week showed weak support for health-care reform. But other pundits argue that Coakley should have had this sewn up without energized Republicans or wavering undecideds being such a factor.

4. Liberals should have quit griping about health-care compromises. Obama was reasonable, but the most liberal Democrats—diehard public-option backers, for example—made voters think reform as it stands now was a major disappointment.

Proponents: Bernard Avishai, Mickey Kaus, Robert Gibbs, Eugene Robinson, Fineman (again)

Prime Example: "We can look no further than Howard Dean, and MSNBC, and Arianna Huffington, and, yes, some columnists at the Times and bloggers here at TPM—you know, real progressives—who have lambasted Obama again and again since last March over arguable need-to-haves like the 'public option,' as if nobody else was listening…Meanwhile the undecideds are thinking: 'Hell, if his own people think he's a sell-out and jerk, why should we support this?' —Avishai at TPMCafe

Is It True? This argument is hardest to judge—how does one measure it?—but intraparty squabbling between Democrats surely helps to drive an "enthusiasm gap" between grassroots Democrats and Republicans, both locally and nationwide.

5. Democrats didn't do enough. Proponents of this theory are a small but noisy group, the same Netroots that the "quit griping" camp attacks, but they say that if Democratic leaders had been more aggressive, the rank and file would have been more energized.

Proponents: David Sirota, Kos (again)

Prime Example: "There is something deeply embarrassing about Democratic voters/groups having to fight with Democratic leaders to get those leaders to even seriously try (much less pass) even the smallest, most modest shreds of their promises. Having to do that evokes feelings of genuine shame—shame in front of the other voters we told to vote for Democrats because it supposedly 'mattered,' and shame when we look in the mirror at a self that may have allowed itself to be unnecessarily duped." —Sirota, at Open Left

Is It True? Like their detractors, the Netroots are relying on emotion. It certainly seems true that disillusionment drained energy from the left-wing base, but would that have made the difference in the Massachusetts race? Lefties likely held their noses and voted for Coakley, and her campaign shouldn't have needed such a staunch base.

6. It was out of Democrats' hands. A.k.a. it's Bush's fault. It wasn't about Obama, and it wasn't about health care. It was about the lingering effects of the economic crisis—which, left-leaning commentators hasten to point out, originated during the Bush administration—that have made the climate terrible for incumbents. Coakley, though not an incumbent, got caught up in that wave.Proponents: Chris Bowers, Chait (again), Dionne (again), Gibbs (again), Silver(again)

Prime Example: "This one is easy: the political environment is terrible for Democrats, and they are going to lose seats in 2010. Duh." —Bowers, blogging at Open Left

Is It True? This theory doesn't have the currency of some of the others, but that's probably because pundits, just like voters, have tired of the "blame Bush" gambit. Health care, despite polling, is still something of an unknown quantity, but no one likes unemployment, and that makes it harder to hold a seat and easier to take it over.