Religion is irrational, no matter which one it is, strictly by definition. If rationality means 'based on reason', than faith-based religion is the exact opposite.
It seems to me that the politician best qualified to lead the country would be the one best able to apply his or her faculties of reason. It is, after all, difficult to pray away a budget deficit.
So why, exactly, would we want a Bible-thumper in the highest office in the land?
Good luck with that, Governor Perry.