Unfortunately a third party would essentially guarantee a dim victory because it would split Republicans in half and the number of Independents who would vote for one or the other. Not many dims would jump ship to a third party or even to the “old” Republicans.
He is a loser regardless if he is nominated.
Your Third Party beliefs are probably accurate, but at least there would be a chance versus no chance with Romney (D or R Ma).
If I have to die in a battle, better a battle I can believe in.