President Joe Biden signed into law Tuesday landmark new federal protections for same-sex and interracial couples, capping both a personal and national evolution on an issue that’s enjoyed growing acceptance over the past decade.

Biden signed the Respect for Marriage Act before thousands of invited guests on the South Lawn at an event the White House said reflected the importance of the moment.

“Marriage is a simple proposition. Who do you love? And will you be loyal to that person you love?” the president asked from the South Lawn. “It’s not more complicated than that.”

Biden said the law he was about to sign recognizes that “everyone should have the right to answer those questions for themselves without the government interference,” and secures the federal “protections that come with marriage.”

“For most of our nation’s history, we denied interracial couples and same sex couples from these protections,” Biden said. “It failed to treat them with equal dignity and respect. And now, this law requires an interracial marriage and same-sex marriage must be recognized as legal in every state in the nation.”

The new law officially voids the Defense of Marriage Act, which defined marriage as between a man and a woman. It mandates that states honor the validity of out-of-state marriage licenses, including same-sex and interracial unions.

As a senator, Biden voted for the Defense of Marriage Act in 1996. The bill signing Tuesday amounted to the culmination of his transformation on the issue. The bill passed in the House with 39 Republicans joining Democrats in support, after getting through the Senate with 12 Republican senators.

Such a bill had seemed improbable for many in Washington not that long ago, even as public opinion on same-sex marriage has continued to shift over the years: 68% of Americans supported same-sex marriage in 2021, up 14 percentage points from 2014, according to surveys from the nonprofit, nonpartisan Public Religious Research Institute.

But the public rallying and push to pass federal protections for same-sex and interracial marriage intensified this year after the Supreme Court overturned Roe v. Wade, sparking fresh fears that the nation’s highest court would also reconsider other existing rights around marriage equality.

The day the Supreme Court’s landmark ruling was issued in June, Biden warned that Justice Clarence Thomas “explicitly called to reconsider the right of marriage equality, the right of couples to make their choices on contraception. This is an extreme and dangerous path the Court is now taking us on.”

He would go on to give similar warnings on the campaign trail leading up to the midterms: “We want to make it clear: It’s not just about Roe and choice. It’s about – it’s about marriage – same-sex marriage. It’s about contraception. It’s about a whole range of things that are on the docket,” he said at a Democratic National Committee reception in August.

For Biden, Tuesday’s event bookended a moment a decade ago that helped spark a national political transformation on the issue. When he was serving a vice president, Biden shocked the country with an unexpected declaration delivered in an interview on NBC’s “Meet the Press”: He came out in public support of same-sex marriage for the first time.

“I am absolutely comfortable with the fact that 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,” Biden said when asked whether he was comfortable with same-sex marriage.

Those words – which Biden insisted in subsequent years were unplanned – marked a stunning personal evolution for the longtime creature of Washington, who as senator had voted to block federal recognition of same-sex marriages and previously insisted that marriage should only take place between a man and a woman.

The interview would also turn out to be a watershed moment in modern American politics, prompting then-President Barack Obama to stake out the same position several days later and giving permission to other national leaders to also follow suit.

“That single interview was a transformative moment in Biden’s development as a politician. In the Senate, as a presidential candidate and as vice president, he always had been very cautious around LGBT issues, afraid of taking any position that opponents could use to portray him as a left-winger,” Sasha Issenberg, author of “The Engagement: America’s Quarter-Century Struggle Over Same-Sex Marriage,” told CNN. “But the reception to what he said on ‘Meet the Press’ was universal praise within his party, especially from LGBT advocates and donors who had previously been skeptical of him.”

Basking in the hero-treatment from liberal activists, Biden would go on to aggressively associate himself with LGBT causes in the years to come, and has in particularly been “unusually bold” when it comes to transgender rights, Issenberg said.

Among the guests invited to the bill signing at the White House Tuesday were prominent members of the LGBTQ community and activists.

They included Judy Kasen-Windsor, widow of gay rights activist Edie Windsor; Matthew Haynes, co-owner of Club Q, the LGBTQ club in Colorado Springs where a gunman last month killed five people in a mass shooting; Club Q shooting survivors James Slaugh and Michael Anderson; and a number of plaintiffs from cases that culminated in the landmark civil rights case Obergefell vs. Hodges, in which the Supreme Court ruled in 2015 that same-sex couples can marry nationwide.

Philanthropist and Democratic donor David Bohnett, who has been an outspoken gay- and transgender-rights activist and longtime supporter of Biden, told CNN that Tuesday’s bill signing could not come at a more crucial moment.

“[Biden] has demonstrated his support for decades for lesbian and gay civil rights, and Tuesday’s signing into law is a reaffirmation of that during this time when rights are under assault,” Bohnett said. “I think we’re here in response to the hateful and discriminatory actions and tactics by so many in the right-wing and so many that want to dismantle the rights that we fought so hard for for a long time.”