When I was twelve, I was interviewed by a doctoral candidate in education and asked what I wanted to be when I grew up. I said that I either wanted to be a philosopher or a clown, and I understood then, I think, that much depended on whether or not I found the world worth philosophizing about, and what the price of seriousness might be.
If somebody harbours delusions, I think that should disqualify them from office, regardless whether the delusions are religious. Letting someone who thinks the god Jehovah will bail him out serve in public office is like letting a man who believes in Santa Claus run a Toys 'R Us. The great enemy of the truth is very often not the lie - deliberate, contrived and dishonest, but the myth, persistent, persuasive, and unrealistic. Belief in myths allows the comfort of opinion without the discomfort of thought.