One of the biggest urban legends of the past few years is the rumor that Barack Obama was raised as a Muslim (variants of this smear are the claims that Obama is Arab and that he was born outside the United States). This canard was first publicized in the Sun Myung Moon-owned (and now-defunct) Insight magazine.
Today in the Moon-owned Washington Times, Frank Gaffney wrote an op-ed in which he make the jaw-dropping claim that "[t]here is mounting evidence that the president not only identifies with Muslims, but actually may still be one himself." Media Matters for America is one of the media watchdogs that have debunked Gaffney's claim (MMFA also cited Gaffney's baseless claims made during the 2008 election about Obama's birth certificate and Gaffney's attempts to link Obama to a "convert to radical Islam" named Khalid al-Mansour).
Tamron Hall of MSNBC addresses the issue: