A friend sent a link today that graphically represents how demography influences the recent votes on gay marriage. Please visit sociological images to see the graph.
A few things that stuck out to me:
1) A lot of places where gay marriage and/or strong civil unions exist have the highest rates of public acceptances. This includes
Massachusetts (#1, gay marriage)
Vermont (#2, gay marriage)
Connecticut (#4, gay marriage)
New Hampshire (#5, gay marriage)
Maine (#6, gay marriage passed by legislature, voted down with Prop 1)
California (#7, gay marriage passed by court, voted down with Prop 8)
Washington (#8, civil unions just affirmed by referendum)
2) Iowa is pretty far down the list (about mid-way down). The overall score of support is ~40%. If gay marriage was not passed at the ballot box in Maine (where support was nominally ~50%), then Iowa certainly wouldn't pass it. My only consolation at this point is that it won't end up on the ballot for a few more years, and even then it might not be put up for a vote.
3) Demography will change this issue, even if people don't change their minds. The young of today will be the old of tomorrow. The old of today will not vote tomorrow. The data points will steadily march rightward to the higher acceptance percentages.
4) If we need to rely on demography, gay marriage has made most of the gains that are possible at this time. Sure, my list above shows that Rhode Island could pass civil unions and/or gay marriage and it would likely stick at the ballot box. But otherwise, no other regions now have majority public support for gay marriage. Ready for a long wait?