The only refinement I might offer is that we don't unilaterally nuke Medina. But President Bush should announce--immediately--that any further fundamentalist Islamic attack upon the United States using weapons of mass destruction will result in the IMMEDIATE vaporization of Mecca.
You are absolutely right when you suggest that the obliteration of Mecca would destroy Islam as a religion, in a way those unfamiliar with Islam would find hard to conceive. It is a threat I think even Bin Laden would understand.
Of course, Saudi Arabia may have something to say about this kind of a threat. But I recognize your hyperbole for what it is, a wish but not a serious policy recommendation.