You must be a NY Times subscriber to read this article about what happens to the GOP if Bush loses, but here is an excerpt:

"For starters, Karl Rove, Mr. Bush's powerful political adviser, would no longer be called a boy genius, although party insiders insist there would be less blame of him and Mr. Bush than might be expected. Assuming that the party hangs on to the Senate, Bill Frist, the majority leader, would emerge as one of the most important Republicans in the country. So would Senator John McCain of Arizona, Mr. Bush's onetime nemesis. Paul Wolfowitz, the neo-conservative who urged the president into war with Iraq, would not."