Mitt Romney and Jon Huntsman Jr. aren't the only Republican presidential hopefuls whose religious beliefs are subject to scrutiny.

After Sunday, Rep. Michele Bachmann's faith sits squarely in the mainstream media's cross hairs.

Appearing Sunday morning on CBS' "Face the Nation," Bachmann opened up about how her Christian faith shapes her political career.

"I became a Christian when I was 16 years old," Bachmann said. "I gave my heart to Jesus Christ. Since that time, I've been a person of prayer. And so when I pray, I pray believing that God will speak to me and give me an answer to that prayer.

"That's what a calling is — if I pray, a calling means that I feel like I have a sense from God. … It means that I have a sense of assurance about the direction I think that God is speaking into my heart that I should go."

Bachmann, a tea party favorite and Republican congresswoman from Minnesota, formally announced her presidential candidacy today in Waterloo, Iowa — her birthplace.

Polling released Sunday by the Des Moines Register shows Romney narrowly leading Bachmann, 23 percent to 22 percent, in early battleground state Iowa. Herman Cain finished a distant third among Republican presidential candidates with 10 percent of the poll votes.

A headline Sunday afternoon at the Christian Science Monitor's website proclaimed, "Michele Bachmann 'the one to watch' as she kicks off her presidential campaign."

"There's no doubt that Michele Bachmann is perceived by many as an interesting and unusual political character," the Monitor writes. "Some of that is sexism, as it is with Sarah Palin. But 'the secret of Bachmann's success is that every time you laugh at her, she gets stronger,' writes Matt Taibbi in a hard-hitting Rolling Stone essay headlined 'Michele Bachmann's Holy War.' "

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