So by that you mean overwhelmingly white liberals?
Maybe in the Twin Cities, but I can't see Iron Range or Red River Valley Democrats supporting gay marriage.
There is not a single major elected official in the Iron Range who doesn't support gay marriage. Duluth is one of three cities in Minnesota (You can probably guess the other two) to recognize domestic partnerships for unmarried couples living together, including homosexuals.
The Democrats in the Red River Valley are mostly the liberals and college kids in Moorhead. Sure there are olds and all in the rural counties, but they don't make up a very large percentage of the state.
Duluth will almost certainly vote for gay marriage. I could see St. Louis County going either way, though it will probably end up going as Duluth goes, but that isn't enough.
Regardless, I think we've seen in a number of states that the percentage of elected officials who support gay marriage at the state level tends to be higher than the percentage that gay marriage recieves in referenda locally.
Having the election in 2012 may allow it to ride Obama's coattails, but I'm still pessimistic about its chances.