These Democrats voted for Mark Critz not because he ran as a pseudo-Republican – he didn’t – but because he positioned himself beautifully as an old school, Roosevelt Democrat, well to the right of those crazy McGovernites in Washington, but well outside the clutches of those evil, pro-big business Republicans like Burns (who want to put a 23% tax on your food). Put differently, Critz probably won in large part because he was aligned closely with the voting preferences of the district. It will be harder for most other Democrats to do this…

The Democrats’ problem has been overwhelmingly among Independents. And those voters don’t show up at a closed primary state like Pennsylvania on Primary Day. Indeed, if you read Jay’s piece, you’ll see that Independent voters probably cast an incredibly small number of ballots in PA-12, along the lines of 10% of the vote. If the Massachusetts, Virginia, or New Jersey electorates had been anywhere near 62% Democratic, 10% Independent, and 28% Republican, Scott Brown, Bob McDonnell, and Chris Christie would have been swamped…

I do think that PA-12 is a good datapoint for Democrats who were worried about a 1938-style 80-seat blowout. That appears less likely after last night. And it’s at the least a PR debacle for Republicans, who had talked up their chances in the district, only to lose, big time. But even with that conclusion, we must be careful about extrapolating too much. All of last night’s elections were driven by uniquely local circumstances, and it is far from clear that key features from any of them are replicable in November.