Thought Experiment
Just for fun, think about this:
If a child is born to a Christian father and sent to a church school system for the about first 12 years of his life, social conventions being what they are, you'd assume child was a Christian. Since Obama's father was a Sunni Muslim and Obama was registered as a Muslim and attended a Muslim school in Indonesia why is he not thought of as a Muslim? In Islam, a child born to a Muslim father, irregardless of it's mother's religion is always assumed to be a Muslim under Islam. I don't remember Obama ever saying he renounced Islam and accepted Christianity, his attendance at a radical anti-White black fundamentalist church notwithstanding.
Another oddity here is that there has seemingly been no fatwas against Obama for leaving Islam. It is virtually automatic that any Muslim openly stating that he is leaving Islam will at least be shunned, jailed, flogged or killed if possible. There have been several radical terrorist types who have called for Obama's death, not because he left Islam, but rather because he is seen as an enemy to whichever Muslim thug he happens to be attacking at the moment. After all, more Muslims are killed by other Muslims than by kuffars.
I'd say the reason there's been no fatwa is because Obama is understood by the Muslim street to be practicing takyya in order to fool the kuffar.