In fact, Obama has been quite open about his faith in the books he has written and in interviews he has given. As The Washington Post reported recently, "Obama did not grow up in a religious household and became a practicing Christian as an adult. He has written more extensively about his spiritual awakening than almost any other modern president, addressing it in two books before he was elected to the White House and in more than a dozen speeches since."

In his book Dreams From My Father, Obama referred to his mother, Ann Dunham, as a "witness for secular humanism," although at other times he has called her a Christian. His father, Barack Obama Sr., has been described as a lapsed Muslim who later became an agnostic. (In 2004, Obama gave a lengthy interview about his religious beliefs to a reporter at the Chicago Sun-Times. You can read it here.)

This background is interesting, but what's more telling are the president's choices. He chose to become a Christian. In his early 20s while working as a community organizer in Chicago, Obama joined the United Church of Christ (UCC).

The UCC is a liberal Christian denomination that holds progressive stands on issues such as marriage equality, women's rights, economic justice and so on. Barry W. Lynn, Americans United's executive director, is a UCC minister. Many bigots have a problem with the UCC - over the years, I've heard plenty of Religious Right leaders assert that Barry isn't really a Christian because he disagrees with their far-right, fundamentalist theology - but whether they like it or not, it is a Christian denomination.

I think it is safe to assume, given the evidence, that Obama is a Christian. This won't stop the nitwit brigade, of course. Last year, the appalling evangelist Franklin Graham asserted, on the basis of no evidence whatsoever, that Obama's mother was Muslim and this must have influenced him.

The fact is, in a society where freedom of conscience is the rule and the government doesn't presume to meddle in people's private religious choices, folks can and do change their beliefs. In a theoretical world where Obama was raised a Muslim, a conservative Christian or a Zoroastrian, he might still have ended up in the UCC. I know plenty of people who have left fundamentalist Christianity or ultra-conservative forms of Catholicism to become atheists, liberal Christians, Unitarians and so on. (And I know some people who have gone in the other direction.) Chances are you do too.

What Obama believes, how he prays or who he prays to are less relevant than what he says about freedom of conscience, separation of church and state and tolerance. And his track record here, while not spotless, is pretty good. Obama has celebrated our nation's religious and philosophical diversity and repeatedly stated his belief that tolerance is a fundamental principle of American public life. I expect he'll do so again at the Islamic Society of Baltimore.

I don't doubt the sincerity of Obama's Christian faith. Nor do I doubt the sincerity of, the Christian faith of, say, U.S. Sen. Ted Cruz (R-Texas). But I get the impression that in Cruz's case, his interpretation of Christianity - an interpretation that many Christians don't share, by the way - would become the basis for law and public policy. That's the key difference.

When I hear Cruz or other politicians talk about building a "godly" society or taking the nation "back to 'Judeo-Christian' values", I have to shiver. There is no shared consensus on what a "godly" country would look like, and I suspect Cruz's vision clashes sharply with the visions held by many other Americans.

What many in the Religious Right want isn't tolerance, it's theocracy. Their effort to force us all to live under their "righteous" rule is the real threat, not half-baked conspiracy theories about a clearly Christian president who's actually a "secret Muslim."