So Clark was qualified to be President because of him military service (albeit at a much higher level than McCain) but McCain's years of service in the Senate (and Clark's lack of political experience) are non factors? That Senators don't evaluate budgets, look witness in the eye and decide their veracity, or manage their office or campaigns? That does not compute.

As far as high ranking generals are concerned, the verdict is mixed as to their competence as President. Grant gets an F, Eisenhower gets a B+ (from most historians). Many of the post civil war presidents were general officers, don't ask me which, weakest part of my knowledge of American history, but none were really army commanders. I don't think I'd throw "Old Hickory" into the Grant/Ike mould.