What If Lincoln Chafee (who had considered running in New Hampshire on an anti-war platform) had indeed challenged George W. for the GOP nomination in 2004? How far could his campaign go?
I can't see it going anywhere. Chafee is one of those New England Republicans like Olympia Snowe who is really just a Democrat who accidentally put an R next to his name. He is pro-choice, pro-gay marriage, anti-death penalty, pro-environmental regulation, anti-war, pro-tax hikes, anti-war, etc. That may count as "Republican" in Rhode Island, but not anywhere else. It would be a minor irritation, but he would get stomped repeatedly in primaries until he finally dropped out. Keep in mind that Bush was still very popular amongst Republicans at this point. Though he had lost a bit of his popularity amongst Democrats and Independents, he hadn't yet gone into the tail-spin that he did by midway through his second term. Chafee might get a bit of media coverage out of it, just because it would be an interesting story, but there's no way he could ever make the race even remotely close.