The poll also showed most Americans now believing that the U.S. Constitution should trump state laws on gay marriage by nearly a 2-to-1 margin. Interestingly, both supporters and opponents of gay marriage agree on this front, evidence that both feel confident headed into the Supreme Court's deliberations.
The poll also found that fewer than a quarter of Americans now see homosexuality as "something people choose to be." Nearly three-quarters of those who do not believe homosexuality is a choice support gay marriage; by contrast, nearly seven in 10 who do see it as a decision oppose same-sex weddings.
On Monday, White House press secretary Jay Carney said that President Obama believed it was a "good thing" that attitudes were shifting on gay marriage.
"It's testimony to how far this country and how quickly this country has traveled," Carney said.