Religion and politics collided once again this month as religious groups -- led by Catholic bishops -- objected to requirements to provide contraceptive-covering insurance in President Barack Obama's health insurance rules. America's widely varying levels of religious commitment, even within denominations, makes the outcome of such firestorms hard to predict.
It's turned into quite the campaign issue, which has pollsters wondering whether religion can really tip the scales. Catholics represent about one in four adults in America, which makes the backlash from bishops to Obama's new regulations potentially consequential. The rules -- which Obama later modified -- would have required religiously affiliated institutions to provide health plans that cover birth control, a practice with which they have a moral disagreement. Alienating such a large group could severely endanger his chances at re-election in November.
But Catholics, like Protestants and other religious groups in the United States, are far from monolithic. Only one in three self-identified Catholics reported attending Mass every week in a January Washington Post-ABC News poll. And even that figure may be an overestimate -- given Americans' tendency to say they are more churchgoing than they actually are.
Obama's popularity among Catholics hasn't taken a big hit, at least in the short term. His overall approval rating among Catholics in Gallup polls ticked down from 49 to 46 percent amid the controversy, a change within the margin of sampling error. While most Catholics in a Pew poll released this week said religiously affiliated employers should not be required to pay for contraceptives, just 15 percent said they believe using contraceptives is morally wrong.
So how much could this affect the 2012 campaign? Catholics represent just one aspect of America's complex religion and politics calculus. Among Protestants, white evangelicals are a cornerstone of the Republican base, while white mainline (or non-evangelical) Protestants represent a key swing voting group. Black Protestants are overwhelmingly Democratic.
For white evangelicals, religion seems to be making more of a difference in the Republican primary than it will when Obama is on the ballot. Romney has struggled to win evangelicals in early primary contests in Iowa and South Carolina, but national polls show evangelicals overwhelmingly back Romney in a matchup against Obama.