 Is there anything that you would look to, you personally, not anybody else, not other pundits, not even perhaps family members, that you would look to to say, if I see that, I will reevaluate? Biden said he'd leave the race only if his doctor said he had a medical condition that would make him unable to serve. But there's more to do, and I'm reluctant to walk away from that. Christopher Cruz, CBS News.