According to a Nobel prize winner Paul Krugman, the driving force behind the town hall mobs is race.

But while the organizers are as crass as they come, I haven’t seen any evidence that the people disrupting those town halls are Florida-style rent-a-mobs. For the most part, the protesters appear to be genuinely angry. The question is, what are they angry about?

There was a telling incident at a town hall held by Representative Gene Green, D-Tex. An activist turned to his fellow attendees and asked if they “oppose any form of socialized or government-run health care.” Nearly all did. Then Representative Green asked how many of those present were on Medicare. Almost half raised their hands.

Now, people who don’t know that Medicare is a government program probably aren’t reacting to what President Obama is actually proposing. They may believe some of the disinformation opponents of health care reform are spreading, like the claim that the Obama plan will lead to euthanasia for the elderly. (That particular claim is coming straight from House Republican leaders.) But they’re probably reacting less to what Mr. Obama is doing, or even to what they’ve heard about what he’s doing, than to who he is.

That is, the driving force behind the town hall mobs is probably the same cultural and racial anxiety that’s behind the “birther” movement, which denies Mr. Obama’s citizenship. Senator Dick Durbin has suggested that the birthers and the health care protesters are one and the same; we don’t know how many of the protesters are birthers, but it wouldn’t be surprising if it’s a substantial fraction.

And cynical political operators are exploiting that anxiety to further the economic interests of their backers.

Does this sound familiar? It should: it’s a strategy that has played a central role in American politics ever since Richard Nixon realized that he could advance Republican fortunes by appealing to the racial fears of working-class whites.

Many people hoped that last year’s election would mark the end of the “angry white voter” era in America. Indeed, voters who can be swayed by appeals to cultural and racial fear are a declining share of the electorate.

But right now Mr. Obama’s backers seem to lack all conviction, perhaps because the prosaic reality of his administration isn’t living up to their dreams of transformation. Meanwhile, the angry right is filled with a passionate intensity.

And if Mr. Obama can’t recapture some of the passion of 2008, can’t inspire his supporters to stand up and be heard, health care reform may well fail.