Perot may not have been full-fledged insane, but I think he even edged out McCain in the megalomaniacal department. I certainly remember his infamous performance in his tv debate with Gore on NAFTA, and he ended up making Gore look not only rational, but like a statesman.
I think a lot of GOP primary voters would vote for McCain or even Giuliani. There's an entire contingent of folks who take an instant dislike to any candidate who's opposed by conservatives, including a lot of the business folks.
contingent who like those disliked by conservative, oppose those liked by conservatives