"He's known"
He's made too many enemies.
The cultural conservatives will attack him because of sabotaging the Nuke Option in the Senate and for snuggling up to the Dems and Media at every opportunity.
Big Business and it's allies like Chamber of commerce and the Club for Growth will attack him via the grassroots for not supporting tax cuts.
He has NO Chance.
McCain voted for Bush's tax cuts. What the hell is the matter with you?