Election 2010 was a vote to repudiate the president's policies.

Everybody knows that. Or at least, everybody is saying it, everywhere.

But if it's true, Democrats who voted against the president's policies should have won more than the general caucus. Democrats who voted with the president should have lost more.

The stats muddy the punditry. Of the 33 House Democrats who voted against health care reform and ran in 2010, why did 21 lose their re-election bids* -- a worse reelection rate than the 56% Republican House victory? Of the 42 House Dems who voted against climate change, why did 25 lose -- again, a worse reelection rate than the national average? And of the Senate Democrats who voted for both the stimulus and health care and ran in November, how did all but two win?**

The answer is voter demographics. Many conservative House Democrats lost reelection for the same reason they voted against health care and climate change. They held down conservative districts that Obama painted with a thin layer of blue when he won in 2008. Many liberal Democrats won reelection for the same reason they felt safe voting for health care and climate change reform. They represented deep blue electorates.

The 2010 electorate wasn't the 2008 electorate. Twenty-nine million members of the Obama coalition stayed home Tuesday, according to ABC. A different slice of America showed up at the polls on Tuesday: same gender, slightly whiter, much older, and much more conservative.

Of course, if demographics drive election outcomes, public policy also drives demographics. Voters stay home because they're frustrated about policies, or they think they'll lose anyway. On the other hand, voters turn out in higher numbers when they're impassioned, usually about something going wrong. Liberals were frustrated, conservatives were impassioned, and the White House agenda stoked these feelings. There is no doubt that the message on Tuesday, boiled down to its basics, was Something isn't working.

But beware arguments that boil down causality to a single variable -- an "it."

Was "it" health care? Only 17% of the voters considered health care the most important issue in this election. Of those more than half voted for Democrats.

Was "it" the president? CNN's exit poll found that only 37 percent of voters "meant to express opposition to Obama."

Was "it" the economy? Of the 16 congressional districts hit hardest by the recession and represented by Democrats, just one of the 16 leaned Republican on Monday.

As National Journal's Charlie Cook notes, this was a perfect storm election. If the economy was this bad and nothing else, it might have been enough to turn the House. If the economy was this bad and Democrats looked feckless to cure it, it might have been enough. If the economy was this bad and Democrats looked feckless to cure it while passing a liberal agenda that galvanized a national movement against the party, it might have been enough. But all of these factors, and many more, on top of the accordion-like nature of midterm elections to mitigate the ruling parties' power, proved utterly fatal.

For the Democratic House, it was death by firing squad. We don't know what killed the majority. There were too many bullets.

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*Edited statistic

**Not counting Sen. Arlen Specter's loss in the Democratic primary.