WASHINGTON — Florida Sen. Bill Nelson reversed his opposition to gay marriage on Thursday, joining a swell of moderate Democrats to do so recently as public support for gay marriage has grown.
Nelson, a Protestant who last week insisted marriage should be between a man and a woman, said he concluded that stance was inconsistent with the beliefs embedded in the Declaration of Independence and his faith.
"It is generally accepted in American law and U.S. society today '. . . that all men are created equal, that they are endowed by their creator with certain unalienable rights, that among these are life, liberty and the pursuit of happiness.' I believe that. The civil rights and responsibilities for one must pertain to all.
"Thus, to discriminate against one class and not another is wrong for me," he said in a statement to the Tampa Bay Times editorial board.
"If we are endowed by our creator with rights, then why shouldn't those be attainable by gays and lesbians? Simply put, if the Lord made homosexuals as well as heterosexuals, why should I discriminate against their civil marriage? I shouldn't, and I won't.
"So I will add my name to the petition of senators asking the Supreme Court to declare the law that prohibits gay marriage unconstitutional."
The high court last month took up two same-sex marriage cases, including one challenging the federal Defense of Marriage Act, which denies benefits to gay married couples.
Same-sex marriage advocates heralded Nelson's move.
"Like many others in the past couple weeks, he's decided to be on the right side of history," said Kevin Nix, spokesman for the Human Rights Campaign. "Once equality catches on fire, there's no going back."
Nelson becomes the 51st senator to back gay marriage, a majority, but 60 senators are generally needed to break procedural hurdles and pass controversial legislation.
Now only six Senate Democrats do not endorse gay marriage: Joe Donnelly of Indiana, Heidi Heitkamp of North Dakota, Tim Johnson of South Dakota, Mary Landrieu of Louisiana, Joe Manchin of West Virginia and Mark Pryor of Arkansas.
(On Friday morning, Heitkamp and Donnelly both came out in favor of gay marriage. "I have concluded the federal government should no longer discriminate against people who want to make lifelong, loving commitments to each other or interfere in personal, private, and intimate relationships," Heitkamp said.)
A handful of Republicans have also changed their mind, including Ohio Sen. Rob Portman, who disclosed recently that he has a gay son and wanted to see him have the right to marry.
On Tuesday, Republican Sen. Mark Kirk of Illinois expressed his support for same-sex marriage, saying, "Our time on this earth is limited, I know that better than most. Life comes down to who you love and who loves you back — government has no place in the middle."
Nelson, 70, is a cautious politician so his move was not entirely expected. At the same time he was just elected to another six-year term, and public opinion was passing him by.
He came to his decision Thursday after many conversations with constituents, said his spokesman, Dan McLaughlin.
"People say, 'Why now?' " McLaughlin said. "Well it's because the cases that went before the Supreme Court and the public debate that has ensued. During this discourse, Sen. Nelson has heard from a lot of constituents. The way he goes about his job is to always treat people with civility and respect and hear what they have to say."
McLaughlin said Nelson was not influenced by other senators who have changed their mind. "He has decided it's wrong and discriminatory."
Nelson long objected to gay marriage on religious grounds. Last week in Tallahassee he told reporters: "I've always stood up for the civil rights of all people, including civil unions. My personal preference is that marriage is between a man and a woman."
Asked if his stance was awkward given the number of politicians flipping, he said, "Not at all."
A national poll released Thursday by Quinnipiac University showed 50 percent of American voters favor same-sex marriage, a high-water mark. Voters favored same-sex marriage 50-41 percent, compared with 47-43 percent in early March.
In July 2008, voters opposed same-sex unions 55-36 percent.
"Many politicians and many Americans are evolving on this issue," said Nix, the advocate. "We see the polling numbers go up and up and up as families sit around the dinner table and talk about it."
Mark Ferrulo, executive director of the advocacy group Progress Florida, said: "Martin Luther King Jr. once said that the arc of the moral universe is long, but it bends toward justice. In Florida that 'moral arc' can be a bit stiffer to bend, but Sen. Nelson certainly helped bend it toward justice, and equality, today."
Florida Republican Sen. Marco Rubio opposes gay marriage on the same grounds as Nelson had until Thursday. Rubio has said the decision should be up to states to decide.
Florida voters placed a ban on same-sex marriage in the state Constitution in 2008.
Times staff writer Katie Sanders contributed to this report.