"Using a Bible to swear upon is a tradition, not a provision.
One could affirm on Margaret Murray's "God of the Witches", an Empire Strikes Back DVD, or nothing at all (as Theodore Roosevelt did)."
Another way of looking at it is would a Muslim country allow a popularly elected official to be sworn in on a BIBLE???? I don't think so.
Of course not.
That's because OUR secular government, built upon the Rule of Law, is stronger than any feeble theocracy.