You're high if you think Dean will beat Bush, especially on a same-sex marriage latform.
This crap is radioactive in the 'burbs on the coasts and in the Heartland. It probably doesn't play that well down South.
Its all part and parcel of what your average suburban voter is interested in government doing - the economy, national security, management efficiency, cognizance of how taxes are raised and spent, infrastructure. Most of them have gay family members, work with gays or have gay acquaintances, and will not sell real well on it as a whole.
And like it or not, those people are the swing moderates that decide an election - it is, in the end, all about the math.