If she won the nomination (which I give about an 0.1% chance to), I'd leave the party.
Why? The moderates had free reign of the pres nod amongst the GOP since 1988. Except for W they all lost. It's time for a conservative to lead. Not Mittens or his Ilk. Ron Paul/Michelle Bachamann 2012 would teapartyslide Obama back to Hawaii.
A guy who the entire media wrote off in 2008 as a kook plus a bimbo who the entire media loves because of the asinine things she says? Yeah, that's a winning ticket right there, in maybe Utah.
Michele Bachmann, in addition to being borderline insane and intellectually challenged, is an extremist. I realize these traits make her extraordinarily popular among the teabaggers, but if Nevada and Delaware are any indications, if she's on the ticket, it will sink the Republicans, whether she's the presidential or vice presidential nominee, i.e. Palin. Sure, she excites the base, but she'll alienate moderates and independents and will just ignite the Democratic/liberal base that despises her so much. Her presence on the ticket would definitely re-energize the Obama Coalition. Make no mistake about it, it'd be an Obama landslide, and then the teabaggers would just have to follow Sharron Angle's lead and exercise those Second Amendment remedies, I guess.
But oh, I hope she gets the nomination. I will campaign for her during the primary season.
