Only some are faithful --- some are truly faithful for sure --- very many are like the Irish Catholics who claim to believe in God but will vote for pro-abortion candidates every time like Ted Kennedy. And many aren't religious. A truck outside the Catholic Church here owned by "hispanics" has one bumper sticker "We Vote Pro-Life" next to one of "Clinton-Gore" so I think many even who are religious just don't know.
Well now you are just getting into the paradox of why any non liberal on social issues would ever vote for a modern Dem. I have been on numerous discussion with Republicans wishing away breathlessly at how they are going to make strides in the black vote going to the GOP (ignoring the last 80 years of polling) when if they were smart and they weren't so worried about being accepted politically by blacks rather than actually being practical and would realize that socially conservative Catholics and Southern Dems are the people desperately in need of an explanation of the GOP's social platform. Unfortunately the Republicans are too busy hiding that plank at the Convention and trying to be a shiney new Dem alternative to blacks (yet again) that they are losing a tremendous opportunity.
Some people treat religion as an ethnic qualifier.