Today is Super Tuesday, so we'll soon have a new dose of data from exit polls and surveys about the voting patterns of Evangelicals, Catholics, Jews, mainline Protestants and other faith groups.

But one interesting trend emerged last week without much notice. In both the Arizona and Michigan Republican primaries, Mitt Romney -- the Mormon -- beat Rick Santorum -- the Catholic -- among Republican Catholic voters.

According to the Pew Forum on Religion & Public Life, Romney won 44 percent of Catholics in Michigan, compared to 37 percent for Santorum. In Arizona, the gap was even wider: Romney won 44 percent to Santorum's 34 percent among Catholic Republicans.

In both states, Santorum won the white evangelical vote. The white evangelical margin was wide in Michigan (35-51 for Santorum), but very narrow in Arizona (35-37 for Santorum).

It's interesting to speculate why this is the case. Santorum, of course, has been campaigning heavily for the evangelical vote, and many evangelicals have a suspicion of Romney's Mormonism.

On the other hand, Catholics -- who've been through the whole religious discrimination thing with JFK -- are not apparently bothered by the fact that Romney is a Mormon.

But the really interesting question is this: How did the contraception controversy affect the Catholic numbers for Santorum? It could be that many Catholics are saying implicitly, "Well, Rick, you may be Catholic, but you're not my kind of Catholic."

This is, of course, pure speculation. Many issues and other factors determine voting decisions. But I suspect the contraception controversy had its share of influence, especially among Catholic women.