The prospect of an electoral rout has unleashed a bitter bout of recriminations both within the McCain campaign and the wider conservative movement, over who is to blame and what should be done to salvage the party's future.
Mr McCain is now facing calls for him to sacrifice his own dwindling White House hopes and focus on saving vulnerable Republican Senate seats which are up for grabs on the same day.
Their fear is that Democrat candidates riding on Mr Obama's popularity may win the nine extra seats they need in the Senate to give them unfettered power in Congress.
My guess is that should Sen. Obama win, there is also going to be a fight on the left, between pragmatists (like myself) and others who would wish for Sen. Obama to govern from a more progressive position. But that's a good kind of fight to have.