Meanwhile, 56 percent of voters say the Constitution and not state laws should determine the legality of same-sex marriage, putting the public at odds with some lawmakers who say it should be left up to the states to decide gay marriage.

Support for same-sex marriage increased by 3 percentage points compared with a March 8 Quinnipiac survey when support was at 47 percent. And it’s a staggering change in public opinion from 2008 — when a Quinnipiac poll found that Americans opposed same-sex marriage 55 percent to 36 percent.