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.