Not important, because the only people I'm going to even consider voting for are the Greens or various socialist third parties, and all those groups support marriage equality, so it's never really going to ever be a determinant of how I vote.
So you wouldn't vote for Sanders or Warren if they ran as a Dem against Hillary?
I
might consider voting for Sanders in the Democratic primary, but I wouldn't vote for Warren. If Sanders runs in 2016 I'd much rather he do so as an independent; I don't think the left will be doing itself any favors if it runs a candidate within the Democratic primaries and gets spanked, and then has to support the party nominee for President in the general election.