What's the least credible claim John McCain has ever made? I'd vote for this exchange with NPR's Steve Inskeep:
As Andrew Sullivan rightly notes: McCain's only known Palin for a couple of weeks. What foreign policy advice could he possibly have sought from her "many times"?
MR. INSKEEP: Given what you’ve said, Senator, is there an occasion where you could imagine turning to Governor Palin for advice in a foreign policy crisis?
SEN. MCCAIN: I’ve turned to her advice many times in the past. I can’t imagine turning to Senator Obama or Senator Biden because they’ve been wrong. They were wrong about Iraq, they were wrong about Russia. Senator Biden wanted to divide Iraq into three different countries. He voted against the first Gulf War. Senator Obama has no experience whatsoever and has been wrong in the issues that he’s been involved in –