Huckabee is a fading star. In a couple years, the religious right will have found a new savior to start hyping up for 2012 (assuming McCain does not win). Although I would love to see him run as an independent to fracture the GOP, neutralizing the chance the religious right ever has of having a big hand in a major political party again, and to see the GOP in chaos.
A lot of people are misunderstanding the Republican base. I remember a soldier telling Ann Coulter at a rally I went to that he would rather take a bullet than have John Kerry be the President. Feelings about Kerry and 2004 set aside, there are a lot of far right wingers out there that would feel the same way about Obama, even if McCain were to absolutely obliterate the economy. They may have disliked Bush but to vote for a Democrat would be sacrilegious. So there won't be a "changing of opinions" if McCain fucks things up even worse.