|Image from Metro.Co.UK|
It is also an irrelevant question. Sure, if Obama weren't really Christian, it would qualify as a "lie," since he's called himself one on many occasions. But it would be a lie that is made by many every day, even probably a few former Presidents. What do I mean by that? Only that I suspect the current President is only nominally a Christian, probably more a skeptic, maybe even an agnostic or atheist. I have no proof, and I don't even really care. Being a Christian is not a requirement for holding office. But it is very nearly an unwritten requirement for getting elected.
But this whole "Obama is a Muslim" thing goes deeper than what his religion really is. It's yet another fear mongering, hate-baiting, divisionist tactic. It's a hair's breadth from the birthers, who believe that Obama was born in Kenya (or Indonesia, or Canada, or the Pacific ocean, or. . .), and thus is not a natural born citizen and thus unable to legally be President of the United States. You can bet that if Obama was a blond haired, blue eyed white guy, none of these sorts of conspiracy theories would exist.