I think the SC primary finished McCain off. In order to beat Bush, he had to damage him so much, so quickly, that the candidacy was destroyed like a popped balloon. The SC win gave Bush enough time to go the distance–which meant that the nomination would be decided by Republican voters, not the independent voters of a few early states with open primaries. McCain never showed any ability to get Republican votes. After SC, McCain was able to win Michigan (which caused heartburn among some Bush supporters) because it was an open primary. But the campaign never had a chance to win after that point. Virginia came later. (Here’s what I wrote about McCain’s comments there at the time.) If I remember the exit polls correctly, McCain’s attack on Robertson and Falwell hurt him among Republican voters–including those who did not consider themselves to be part of the religious Right.