Why shouldn’t Barack Obama say “so help me God” when he takes the oath of office on Jan. 20? That’s what I wondered when I learned of the lawsuit, to be heard by a federal judge this week, which aims to prevent him from doing so. Obama is a religious man who has spoken often and eloquently about God. It seemed to me reasonable that he would want to ask for divine guidance on this, the most momentous day of his life—at such a critical time for our country and the world.