For many of these pundits, his father’s and grandfather’s religion is evidence of Obama’s diverse background and is therefore wonderful; it is also proof that he can “understand” the Islamic world in a way that others cannot. From the perspective of many Muslims, I would guess that the reaction is quite the opposite: he may never have been a Muslim, but given where he spent some of his earliest years in Indonesia it will seem even more strange that he was not, and it will hardly inspire an outpouring of goodwill to know that someone was familiar with your religion and then chose something else instead in later life. At best, I think he would be received politely or indifferently–until people learn about his views on various Near Eastern questions. Rejecting something that is entirely unknown or largely foreign to your experience can be expected; rejecting something you grew up around, even if only for a few years, takes on a different meaning.

But that’s just in terms of literal apostasy; the fact that he is descended from Muslims in the non-West but has become Christian and Western is still not the kind of thing to which I’d expect the Muslim world to thrill.