March 15, 2013 -- intro: Public opinion on same-sex marriage has shifted rapidly in recent years. Here is a look at some of the most high-profile politicians who have changed their opinions on the issue in the past decade.
quicklist: 1title: Hillary Clintontext:Former first lady, senator and Secretary of State Hillary Clinton has been in the political arena for many years, but has avoided an official stance on same-sex marriage until now.
In an interview with CBS News in 2003, Clinton spoke of her opposition to same-sex marriage but said she was in favor of civil unions. She went on to say that she was opposed to the Federal Marriage Amendment that would have defined marriage as an act between a man and a woman.
As a New York senator, Clinton repeated her support for civil unions in 2006 when the state did not extend the constitutional right of marriage to same-sex couples.
In a 2007 ABC News interview, Clinton spoke about the military's "don't ask, don't tell" policy her husband, former President Bill Clinton implemented. Hillary Clinton admitted that the policy was no longer applicable, and that openly homosexual service members should be allowed to serve in the military.
"We are being deprived of thousands of patriotic men and women who want to serve their country who are bringing skills into the armed services that we desperately need," she said.
On March 15, 2013, Clinton officially announced her support for same-sex marriage in a video for the Human Rights Campaign.
quicklist: 2title: Sen. Rob Portman text: Rob Portman, R-Ohio, was once on the short-list of Mitt Romney's 2012 running mates and opposed gay marriage legislation. Portman reversed his conservative stance Thursday in light of his own son's being gay.
Portman told several Ohio newspaper reporters Thursday that when his son, Will, came out to him two years ago, he began to think differently about same-sex marriages.
"It allowed me to think of this issue from a new perspective, and that's of a dad who loves his son a lot and wants him to have the same opportunities that his brother and sister would have, to have a relationship like Jane and I have had for over 26 years," Portman said, according to an interview with the Cleveland Plain Dealer.
Portman also said that he wants part of the 1996 Defense of Marriage Act to be repealed.
"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 in an op-ed piece for the Columbus Dispatch.
According to an interview with CNN's Dana Bash, Portman told Romney "everything" when being considered for the vice presidential role he ultimately didn't get, and also consulted with former Vice President Dick Cheney because Cheney's daughter is a lesbian.
Read more about Sen. Rob Portman's reversal on gay marriage.
quicklist:3title:Dick Cheneytext:In 2004, former Vice President Dick Cheney publicly voiced his supportive stance for gay marriage equality at various points on the 2004 re-election campaign trail. Cheney also mentioned that his daughter, Liz, is a lesbian.
Cheney's remarks were in stark contrast to those of President George W. Bush, who opposed gay marriage and set the administration's policy on the issue.
But Cheney did not actively lobby for same-sex marriage as vice president.
ABC News' Jonathan Karl asked Cheney in July whether he wished he had more actively lobbied for same-sex marriage.
"Why?" Cheney asked. "If I was out there 12 years ago in the first campaign -- in 2000 -- in the debate with Joe Lieberman in front of millions of Americans on live television and I laid out my position then and it hasn't changed, no. I've addressed it and moved on."
Cheney said he does not think gay marriage should be a relevant issue in presidential elections.
quicklist:4title:Joe Biden text:Vice President Joe Biden became the second consecutive vice president to voice public support for gay marriage, beating President Obama to the punch.
In May 2012, the vice president indicated a changing policy on the issue within the Obama Administration when he appeared on NBC's "Meet the Press".
"I am absolutely comfortable with the fact that men marrying men, women marrying women and heterosexual men and women marrying one another are entitled to the same exact rights, all the civil rights, all the civil liberties," Biden said.
The vice president's statement caused a flurry of responses from both the media and the government because the president set the tone for gay marriage policy. At the time, according to President Obama's stance, the administration was in favor only civil unions.
Biden's comments caused a flurry of discussions wondering whether the vice president was speaking off the cuff (as he is known to do) or whether he was seriously signaling changing opinions. President Obama also announced his support for gay marriage a few days later, even though he said Biden got "a little over his skis" on the issue.
quicklist:5title:Barack Obama text:Six months before his second presidential election, President Obama announced his support for gay marriage in May 2012. The announcement reversed his 2008 position that maintained support for civil unions but opposed same-sex marriages.
The change made Obama the first sitting U.S. president to publicly support gay marriage. Many believe the president's new stance helped galvanize support for his campaign in the final months leading up the 2012 election, which he won.
During his second inaugural address, President Obama cemented his position on gay marriage for the duration of his presidency by linking the gay marriage struggle to civil rights movements of the past.
"We, the people, declare today that the most evident of truths -- that all of us are created equal --is the star that guides us still; just as it guided our forebears through Seneca Falls, and Selma, and Stonewall," Obama said.
quicklist:6title:Jon Huntsmantext:Former Republican presidential candidate and Utah Gov. Jon Huntsman supported civil unions but opposed same-sex marriage during his campaign for the Republican presidential nomination. Huntsman officially reversed his opposition to gay marriage in an op-ed piece in the American Conservative in February 2013.
In the piece, Huntsman discussed how the Republican Party would benefit from embracing gay marriage legislation and how marriage should be a source of happiness for all people.
"Today we have an opportunity to do more: conservatives should start to lead again and push their states to join the nine others that allow all their citizens to marry. I've been married for 29 years. My marriage has been the greatest joy of my life. There is nothing conservative about denying other Americans the ability to forge that same relationship with the person they love," Huntsman wrote.
He also stated that Republicans need to address the issue in order to stay relevant in the political arena.
"We are at a crossroads ... the American people will not hear us out if we stand against their friends, family, and individual liberty," Huntsman concluded.
Huntsman has joined 76 Republicans who signed on to the legal brief in support of gay marriage in the Supreme Court's upcoming ruling on the Defense of Marriage Act.
quicklist:7title:Bob Barrtext:Bob Barr led the legislative debate concerning same-sex marriage by authoring and sponsoring the controversial Defense of Marriage Act, which was enacted in 1996.
The act stated that states would only federally recognize marriages between men and women. Additionally, the act stated that states had the option of not recognizing same-sex marriages performed outside of the states where the couple resided.
Since the act was passed and enforced, Barr has officially rescinded his initial position on same-sex marriage and apologized for the portion of the legislation preventing same-sex marriage recognition at the 2008 Libertarian Convention.
Barr supports the Respect for Marriage Act, which would repeal the Defense of Marriage Act.
Read more about how the same-sex marriage debate has changed since 1996.
quicklist:8title:Bill Clintontext:Former President Bill Clinton signed the Defense of Marriage Act into effect in 1996, signaling a lack of support for gay marriage in his administration's policies.
The act federally recognized marriages between men and women, not between homosexual couples. The act also allowed individual states the option of not recognizing same-sex marriages that were performed outside of the states where the couple lived.
Before signing DOMA, Clinton signed "don't ask, don't tell," a policy that allowed homosexuals serving in the military to keep their sexuality secret. Critics of the policy said Clinton was not going far enough in preventing same-sex discrimination, while the president's administration maintained that the act's purpose was to deter homosexual military members from harassment.
In 1996 Clinton told LGBT magazine, The Advocate, that he was staunchly rooted in his opposition for the legislation.
"I believe marriage is an institution for the union of a man and a woman. This has been my long-standing position, and it is not being reviewed or considered," Clinton said.
Well after leaving the Oval Office, Clinton voiced his official support of gay marriage in 2009 during an appearance at the Campus Progress National Conference in Washington. He said that it was wrong for people to stop homosexual couples from marrying, and that he supported states' rights to decide their positions on the issue, rather than involving the federal government.