Sure he could do it...and he would make McGovern look like a winner by the time the election was over. The only scenario I can envision would be if Biden were to have a serious accident or illness that would garner some sort of public sympathy that would carryover into the campaign with a new and healthy VP pick. And if Hillary is chosen, Obama would succumb to illness by Feb.2009.
Sounds like ‘Arkancide’ would be in order.