(NewsNation) — The Democratic-led House of Representatives approved legislation Tuesday to protect same-sex marriage nationwide with the support of dozens of House Republicans — a bipartisan move that would have been unthinkable just a few years ago.

The Respect for Marriage Act, which codifies federal protections for same-sex and interracial marriages, passed the House by a vote of 267-157 on Tuesday. Every Democrat voted in favor, along with 47 Republicans.

As recently as 2011, less than half of Americans thought same-sex marriage should be recognized as valid under the law, according to Gallup polling. Today, a significant majority (71%) support same-sex couples’ right to marry.

“It’s one of the fastest moving social issues we’ve ever seen,” said Ryan Burge, a political scientist at Eastern Illinois University, who pointed out that public opinion rarely shifts more than three to four points on most issues.

In 2021, for the first time ever, most Republicans, 55%, said same-sex marriage should be recognized by the law as valid. Just 10 years ago, less than 30% were in favor.

Today’s Republican majority is still significantly less than the 83% of Democrats and 73% of Independents who support same-sex marriage, per Gallup, but it’s a sign any move by the Supreme Court to overturn the 2015 decision in Obergefell v. Hodges would likely be unpopular across the political spectrum.

Other groups who were once strongly opposed to same sex-marriage have also shifted in recent years. Among those who attend church weekly, support has doubled from 20% to 40% since 2004.

Even among evangelical Christians, Burge’s research found attitudes have become more accepting of same-sex marriage.

“A lot of evangelical pastors just basically said this is not a fight that’s worth having because I’m going to probably push a lot of people away,” Burge said.

How did public opinion shift so dramatically in recent decades?

“I think it really does come down to just people knowing and loving and caring about members of the LGBT community,” said Marina Lowe, the policy director for Equality Utah, an LGBTQ advocacy group. “It’s hard to pass mean-spirited legislation, or deny protective legislation, when you know and care about people who are affected.”

All four Republican congressmen from Utah voted in favor of the Respect For Marriage Act on Tuesday.

The Democratic-led House has moved swiftly to enshrine same-sex marriage in federal law after the Supreme Court overturned federal abortion protections last month.

Many fear same-sex marriage rights could also be under threat, especially after Justice Clarence Thomas suggested that other cases similar to Roe v Wade, such as Obergefell vs Hodges, should be reconsidered.

If that ruling were to be overturned, Lowe says it would strip same-sex couples of dozens of concrete legal benefits afforded only to married couples.

“There are so many families that would be affected by this,” Lowe said. “It’s hard to imagine how you could pull away that right and remove protections that have been there already.”

The bill now moves to the Senate where it will have to win the support of at least 10 Republicans to avoid a filibuster and become law — a realistic possibility given the way opinions on the issue have changed, said Burge.

Two Senate Republicans have already signed on as co-sponsors, including U.S. Sen. Rob Portman of Ohio, who said nearly a decade ago his views on same-sex marriage had changed after his son told him he was gay.

The Associated Press contributed to this report.