And on Wednesday, occasional CJR contributor (and my former professor) Tom Edsall penned a piece for TNR.com that offered a variation on the theme. In the course of arguing that attempting to pass health care reform was a political miscalculation, Edsall cites the sociologist Robert Putnam, whose recent work focuses on the idea that in diverse environments, rates of altruism, trust, and cooperation decline:

Putnam’s findings offer critical insight into the explosive growth of the Tea Party movement and the strikingly sudden collapse of support for the Democratic Party. They suggest that the populace, especially the white populace, is on a psychic hair trigger. The demographic transformation of the country and the birth of multicultural America have made this group extremely status anxious—an anxiety that the recession obviously heightens. They are in a mood, to borrow Putnam’s phrase, to “hunker down.”

And it is precisely this anxiety that is such an impediment to empathy. They view themselves as only marginally better off than those they perceive as the recipients of new government benefits. They look at health care reform and worry that they have little or nothing to gain and much to lose. In the end, Democrats failed to tailor their salesmanship of health care reform to allay the qualms of these voters, of the white working class.

This is not exactly the idea advanced in the MacGillis article—Edsall’s claim isn’t specific to Massachusetts, and Brown’s health care message wasn’t rooted in appeals to racial or class identity. But the underlying dynamic, of in-group solidarity in a time when resources are perceived to be scarce, is similar.

So is this analysis accurate? It’s hard to say; as we’ve been noting this week, speculation about why Massachusetts voters made the choice they did is bound to be… well, speculative. And, as Yglesias notes, if voters are behaving this way it would be “at odds with the fact that voters rarely explicitly conceive of themselves as acting on self-interest.” Still, in the fight to explain what this election was about, it’s another contender.

Greg Marx is a CJR staff writer. Follow him on Twitter @gregamarx.