AEI has a useful study, summarizing all the data from many polls, and giving some historical perspective. There are two obvious inferences. The country is obviously divided on this: around 50-50 on a constitutional amendment, and, with some variations, a rough 30-30-40 split on support for marriage, civil unions or nothing at all. This seems to me to work in favor of the federalist answer, with various options being tried out across the country. But the other finding of all the polls is equally indisputable. There has been a massive shift in the last thirty years toward acceptance of gay equality. This has continued despite (or even because of) the campaign against marriage rights by the Christianist movement. The proportion of people who say they know a gay person has doubled in twenty years. In my view, that has been the real agent for change. And if gay people want their civil rights, they know what to do. If you’re in the closet, you have no one to blame for your inequality but yourself.