Republicans would have:
The N.R.A. Wackos
The Money (corporations)
The Military
The Democrats would have
Hollywood Propaganda
Some foreign support
and More Hippies than you can shake a peace sign at
I'd go with the Republicans though I think with some foreign support the Democrats would put up quite a fight. If they all don't move to France and Canada first.
And before anyone says anything I'm joking!
Seriously though, I'd hope everyone in this country would understand that Civil War would only lead to amazing casualties to solve an issue that can be easily be fought with media and the ballot box.