Last week the Pew Forum on Religion and Public Life released a new analysis of trend in political party identification by various religious communities. The overall finding is that, between 2008 and 2010, Republicans made significant gains among all religious groups, with the largest gains coming among White Catholics (+8 percent points), Jews (+9 points), and Mormons (+12 points). Among all Catholics, Republican affiliation increased by 6 percentage points.It is interesting to note, however, that Catholics overall are still more likely to say they lean toward the Democrats (48%) than toward Republicans (43%), despite the 49%/42% advantage that the Republicans enjoy among White Catholics. Although the data on the Pew web site do not break out other ethnic groups among Catholics, my surmise is that the views of Hispanic Catholics (who tend to lean Democratic) are the reason for this difference.The Republican advantage among White Catholics is particularly pronounced among those under 30. There is a 14 point gap between White Catholics under 30 who identify as Republicans (54%) and those who identify as Democrats (40%). However, the numbers were almost exactly reversed (41% Rep/51% Dem) four years ago and the margin of error for this subpopulation is somewhat large.The key question, of course, is what is driving both the absolute differences and the changes. Given that the Republicans have gained among every religious groupeven among relatively liberal Jews and mainline Protestantsmy guess is that the cause is not deeply tied to issues related to religious identity or the culture war. The fact that the largest swings between 2008 and 2012 are among younger voters suggests that reduced economic opportunities for this cohort may be driving most of the dissatisfaction with the Democrats.Nevertheless, the Democrats would be advised to pay close attention to these numbers. While White Catholics are a decreasing share of the overall Catholic population, they remain a strong force in several key swing states, including Pennsylvania, Ohio, Wisconsin, and Michigan. President Obamas weakness among many of these voters may or may not be deeply tied to their religious views, but it is a connection he ignores at his peril.