Last night, Rick Santorum finished second in the Iowa Republican caucuses, a mere eight votes behind Mitt Romney, propelled by strong support from Evangelical voters. According to entrance polls, Santorum received the votes of a third of Evangelical voters. You might say that’s not a big deal, since two-thirds of Evangelical votes went to other candidates. The thing is, Santorum is a Roman Catholic, and the Evangelical/Catholic divide was traditionally a strong one in American politics. The idea that a Northeast Catholic would get strong support from Midwest Evangelicals — far more than Evangelical candidates in the race like Michele Bachman and Rick Perry — shows how much the politics of American religion has changed in the last two generations. On many politically-salient issues, Evangelicals and Catholics today make common cause. The results from Iowa offer more evidence that the  divide in contemporary American politics is not so much between religions, as between voters who have traditional religious commitments and voters who don’t.