Frank Foer has an interesting theory: As the Washington Post reports today, Muslims in the United States—well, at least in the Washington, D.C., area—seem to be migrating out to the exurbs, where an increasing number of mosques are dotting the strip-mall landscape. Since exurbs tend to have considerably less social tension than urban areas do, this might explain why there seem to a lower percentage of pissed-off Muslims, and a lower percentage of Muslim radicals, in the United States than in Europe—where (perhaps) a greater number of young Muslims dwell in urban areas.

Well, assuming everything assumed above, maybe that's true. Then again, exurban living doesn't seem to have stopped the evangelical right from getting so bad-tempered all the time; though perhaps evangelicals are a good deal less angry out among their Home Depots and Olive Gardens than they would be if, say, they were forced to live in the Castro district here in San Francisco. No, but really, David Brooks is probably onto something and one shouldn't underestimate what sort of effects the great suburban migration has had on the United States over the years. If it can help drive a stake through the heart of the welfare state, it can probably attenuate Islamic radicalism.

UPDATE: Richard Posner cooks up an alternate theory: Maybe the fact that Americans work far more than, say, the French do—some might say we obsess over it—makes the United States a more gratifying place for immigrants to live. Now sure, the sort of restrictive labor laws and high unemployment rates you find in France and Germany might make it more difficult for immigrants to find work. And that in turn might lead to a good deal of resentment. On the other hand, Britain has fairly "liberal" labor laws, a lower unemployment rate than we do, and yet plenty of angry immigrants, apparently.