John McCain winning the South Carolina Primary is very hard, because George W. Bush is more of a Southerner than him. Perhaps McCain could win Nevada, and coupled with an ATL release of Bush's drunk driving arrest from the 1970s, this gives him the momentum he needs to defeat Bush?
Anyway, most users on this board agree that John McCain would defeat Al Gore by a larger margin. They explain this by noting that McCain would run as an independent maverick against the political establishment. However, I believe that this could go the other way as well. I personally think Gore would defeat McCain, because not only would conservatives not be satisfied with him as their nominee, he has less charisma than Bush, and is weak on foreign policy issues. McCain would stress foreign policy issues and his long record of service, but could not attack Gore on the good economy.
Come the 2002 midterms, George W. Bush doesn't run for re-election as Governor of Texas to step aside for Rick Perry. Bush most likely runs for President again in 2004.