Simple: act like a Christian.
Barack Obama keeps getting accused of being a closet muslim by some people. I actually don’t think that’s true. I think Barack Obama is a secular atheist who only talked God and religion to get people to vote for him.
The man has repeatedly turned a blind eye to Christian persecution, his administration has been deeply hostile to people of faith, he has shown himself often sympathetic in his tone to Islamic radicals, and he has never spoken insultingly of Islam as he has Christianity.
When the Pope arrives, the President will further insult the faith by having people in active and celebratory rebellion to Christianity greet the Pope.
If the President wants to stop being accused of being a muslim, he should either fess up that he isn’t a believer in anything other than himself or start acting like the Christian that he claims to be.