Most recent polls have shown more Americans supporting same-sex marriage than opposing it, and majorities in Maine and Maryland voted to give gay and lesbians the right to marry last November at the ballot box. Politicians, too, perhaps sensing a new political environment, have started coming out in favor of marriage equality - at times reversing significantly from their past views on the subject.
Here, CBSNews.com rounds up some of same-sex marriage's most prominent political flip-floppers.
Joe BidenVice President Joe Biden seems to have, perhaps unwittingly, gotten the ball rolling for what now looks like widespread Democratic support for same-sex marriage. In an appearance on NBC last may, the famously unscripted VP made it clear that he was "absolutely comfortable with" the idea of same-sex marriages - beating President Obama, who was at the time still "evolving" on the issue, to the punch.
"Men marrying men, women marrying women, and heterosexual men and women marrying another are entitled to the same exact rights, all the civil rights, all the civil liberties. And quite frankly, I don't see much of a distinction beyond that," said Biden, who had long supported civil unions but previously stopped short of explicitly endorsing same-sex marriage.
At the time, Biden's casual announcement caused something of a media firestorm: He had managed to both overshadow the president on the issue and force his hand on it. Later, Biden said he apologized to the president for the gaffe. But his change in position led to the president's own change of heart
President ObamaDays after Biden announced his support for same-sex marriage, President Obama followed suit. In a dramatic sit-down interview with ABC's Robin Roberts on May 9, Mr. Obama said that "same sex couples should be able to get married." He specified, however, that law relating to the issue should be determined on the state level.
This was not Mr. Obama's first flip-flop on the issue: In 1996, as a candidate for the state Senate in Illinois, he offered "unequivocal" support for same-sex marriage before changing his position. As a candidate for president in 2008, Mr. Obama said he supported civil unions but not same-sex marriage.
Now, the president is vocal in his support for same-sex marriage, and his administration has declined to defend the Defense of Marriage Act (DOMA), a federal law that defines marriage as between one man and one woman and which will be challenged at the Supreme Court Wednesday.
Bill ClintonFormer President Bill Clinton is remembered as a socially liberal president, but it's his signature that the Defense of Marriage Act - the very bill that gay rights advocates are trying to get overturned in the Supreme Court this week. Since approving DOMA in 1996, however, Clinton has reportedly been haunted by the decision, which was seen as a political move rather than an ideological one. By 2009, Mr. Clinton was publicly regretting the decision; in 2011, he endorsed New York's same-sex marriage law. Finally, this month, he penned an
Hillary ClintonHillary Clinton remains mum about her future political aspirations, but her recent announcement formally backing same-sex marriage was seen as a sign that she's not about to be left behind her fellow Democratic politicians on an issue could be pivotal in 2016. Earlier this month, she released a video via the Human Rights Campaign expressing her own "evolution" on marriage equality, and her belief that, since gays and lesbians are "full and equal citizens," they "deserve the rights of citizenship."
"That includes marriage," she said in the video. "That's why I support marriage for lesbian and gay couples. I support it personally and as a matter of policy and law."
Her announcement marked the latest shift over an issue on which she has been evolving for years. In 2007, Clinton rejected DOMA but then clarified through a spokesperson that she was objecting to the law's ban on federal recognition of same-sex marriages, not the idea that states have authority to determine the law independently.
Before her announcement, Clinton had long supported civil unions between same-sex couples, and she also backed the 2011 law that legalized same-sex marriage in New York State.
Dick CheneyFormer VP Dick Cheney, a combative and controversial Republican who served under a president who pushed for a constitutional ban on same-sex marriages, was seemingly an unlikely candidate to lead the charge in its favor. But in 2009, the he endorsed it publicly, citing the idea that "freedom means freedom for everyone" - including his daughter, who is a lesbian.
"As many of you know, one of my daughters is gay and it is something that we have lived with for a long time, in our family," he said in 2009. "I think people ought to be free to enter into any kind of union they wish. Any kind of arrangement they wish."
Cheney said then, as he had in the past, that he believes the issue should be determined by state legislatures.
Sen. Rob PortmanSen. Rob Portman, R-Ohio, who was on the short list to be Mitt Romney's running mate last summer, has long been considered an adamant social conservative - and actually co-sponsored DOMA back in 1996. This month, however, he stunned people on both sides of the aisle with a public reversal on the subject: Influenced by his son, who is gay, Portman came out in favor of same-sex marriage.
"I have come to believe that if two people are prepared to make a lifetime commitment to love and care for each other in good times and in bad, the government shouldn't deny them the opportunity to get married," he wrote, explaining his decision in an op-ed this month.
"My position on marriage for same-sex couples was rooted in my faith tradition that marriage is a sacred bond between a man and a woman. Knowing that my son is gay prompted me to consider the issue from another perspective: that of a dad who wants all three of his kids to lead happy, meaningful lives with the people they love, a blessing Jane and I have shared for 26 years."
Democratic senatorsAmid this recent boon of support, two prominent Democratic Senators decided to join the bandwagon: This week, Sens. Claire McCaskill, D-Mo., and Mark Warner, D-Va., came out for marriage equality.
As Democrats in conservative-friendly states, their support signals a sense that backing same-sex marriage is no longer considered a major political liability.