It's now become "unthinkable" to question McCain's veracity because--hey--he was a POW.  This is going to be his defense for everything, and the people running his campaign (who are paid to win, not to follow rules) will use it as a shield for everything that they do, whether it's skirting the rules of a debate or questioning his judgment on foreign policy matters.  
This is why his campaign freaked out (note: link is to wanktastic slate article) and the media flipped out that he was "tone deaf."  That is, simply, nonsense.  What Clark said was that you don't automatically accept his judgment because he was a POW.  If McCain loses this part of his persona (which is all he's running on), he loses period.  That's why, in my own view, the McCain folks went ballistic with the pushback.  The media's inability to grasp this basic point is an entirely separate matter.
Having won that round against Clark, the McCain bunch is going to use it for everything, and why shouldn't they? The media is going to give them a pass until it becomes simply ridiculous, and by that time the damage may well have been done.  That shield licenses virtually every slimy tactic that the Rove deputies can come up with.  "Obama wants to be president more than win the war.  Take it from me--I'm a former POW."  You can't win an argument against persona, and persona is all that McCain has.  
Clark should be sent out on the airwaves, and the theme of his statements repeated over and over again.  The Georgia fiasco, and McCain's repeated bellicose and irresponsible statements provide a perfect example of his judgment, and his POW status simply doesn't enter into it.  He would have started world war III if he were in the white house.  The D's could learn from Rove: take away your opponent's strength.  It can be done without purple heart stickers.