I think both sides would back off campaigning for a few days, Edwards would select Clark as his running mate and sympathy for the Dems allows the Dems to cruise to victory.
Edwards/Clark--56% 386 EV
Bush/Cheney--43% 152 EV
Why? No one gave a sh**t about John Kerry. With the top of the ticket gone, there would be no one left to vote for. If Edwards wouldn't lose votes, he sure as Hell wouldn't gain any either.
Sympathy votes only work for incumbents, either way.
Hmm, must have gotten up on the wrong side of the bed today, Chris...
Plenty of people cared about Kerry, and did vote for him, not just against Bush, if that's what you are suggesting.
I also think that in retrospect, Edwards would have done better than Kerry. More appeal to moderates and populist voters. I think Edwards would have carried Ohio.
Of course, his lack of experience would have played against him, though exactly how much, it's hard to say.
And sympathy votes most certainly do work for the challenger. Case in point: the 2000 Missouri Senate race.