In a poll billed as the "first public opinion poll of 2013 on marriage rights for gay and lesbian couples," a majority of Americans—"91% of Democrats, 75% of Independents, and 56% of Republican voters"—believe that gay marriage is a Constitutional right. I think this second part of the poll is even more exciting than that:

With nine states now allowing same-sex couples to legally marry and more moving in that direction, voters almost universally believe that it will be legal nationally in the next five to ten years (83%), and 77% believe that it will be legal nationally “in the next couple of years” – regardless of their personal opinion on the issue. This represents a sizeable increase since 2011 when 72% believed it would happen in the next five to ten years, and 67% believed it would happen in “the next couple of years.” While Democratic voters feel most strongly (82% believe it will happen in the next couple years), huge margins of Independents and Republicans feel the same way (73% and 70% respectively).

This is exciting stuff. Go read all the heartening poll results.