Ali Eteraz differs:
Islamic law recognizes abandonment by the biological father. Obama's Kenyan father abandoned Obama. As such, any religious imprimatur he may have had over Obama -- which is already a stretch since the man was an atheist -- is null and void. In such a situation, Obama's mother's religion is controlling. She was not Muslim. Even if someone makes the argument from patriarchy: that Obama's paternal grandparents were his rightful guardians, that would fail since they also constructively abandoned him.
There is a corollary issue here: what about the fact that Obama's second father, the Indonesian, was a "non-practicing Muslim." Doesn't his faith transfer over to Obama? The answer is no.
This is outside my area of expertise. I'm just glad that the meme that Obama is still a Muslim is no longer currency in informed circles. Luttwak's point would still hold, of course, if enough Muslims believed it. And the level of paranoia and stupidity in some areas of the Middle East eclipses that in Harlem or West Virginia. But what can anyone do about people willingly believing demonstrable lies?