Does it completely hurt McCain's chances?
his platform is "I know the military, I was a POW". Well, clark served a lot longer, at higher levels, and has worldwide connections. He's very credible and would give the ticket military foreign policy experience.
Plus... we all know bill and hilary are/were domestic presidents.... bill fixed the homefront, turned around the economy. The only complaint is that he got a BJ, and let the military slip. Imagine the promise of hilary fixing the homefront while wes clark kept the world in line.
It could undermine his chances at winning. he doesn't want to compare military records.