Rick Santorum has positioned himself as the leading religious candidate in the Republican presidential field, speaking out strongly on social issues and stressing his devout family life. But while Santorum, a Roman Catholic, has performed well with evangelical Christian voters, who propelled him to victory in Alabama and Mississippi last week, he has yet to win the Catholic vote in any state.

Santorum's latest setback came in Sunday's Puerto Rico primary. When the heavily Catholic island voted, it was Mitt Romney who crushed his rivals.

Asked by Sandy Rios of American Family Radio on Monday morning about his failure to catch fire with his co-religionists, Santorum seemed exasperated by the trend. In searching for answers, he argued that the religious fervor of Catholics is less uniform than that of evangelicals, who have traditionally been a strong part of his base. The former Pennsylvania senator said:

You know, I really wish I could tell you. The bottom line is that we do well among people who take their faith seriously, and as you know, just like some Protestants are not churchgoing, they are folks who identify with a particular religion but don't necessarily practice that from the standpoint of going to church and the like. And I think folks who do practice their religion more ardently, I think we do well [with them].

Santorum's self-critique sounds about right. Observing that the candidate's views are as likely to turn away American Catholics as attract them, the Associated Press reported on Sunday that "less than one-quarter of Catholics attend Mass weekly. Most use artificial contraception, support gay civil unions or marriage, and hold other views contrary to church teaching. Religious conservatives have called these Catholics "CINOs" -- Catholics in Name Only."

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