I can't see him being more than a Tom Vilsack or Ron Paul like candidate.
How are they comparable?
Vilsack was a moderate candidate who hoped to have a real shot
Paul was a fringe candidate devoted to rallying his cause
Gary Johnson 2012! I think I did a TL dreaming about this scenario
I meant to say that he could either be a guy who announces his run for the presidency, but decides at the last minute that he doesn't want to run; or a guy who (as you said) rallies people for his cause.
I'll give you some credit, if the Iraq War isn't an issue by 2012, he might have a chance. I have to check out his positions on Israel/Iran/Palestinians first to make sure, though.
PS. I can't really see him rallying the evangelical base. Maybe its just me.