President Joe Biden signs the Respect for Marriage Act at the White House, Dec. 13.

Photo: brendan smialowski/Agence France-Presse/Getty Images

In the oral argument for Obergefell v. Hodges (2015), one exchange set off alarm bells among social conservatives. Justice Samuel Alito asked Solicitor General Donald Verrilli if the legalization of same-sex marriage could cause universities and colleges to lose their tax-exempt status if they didn’t recognize same-sex marriage—as Bob Jones University had for prohibiting interracial dating in the 1970s. Mr. Verrilli’s answer was ominous for institutions with traditional views on sex and marriage. “It’s certainly going to be an issue. I don’t deny that,” he said. “It is—it is going to be an issue.”

Mr. Verrilli stumbled, but a simple one-word answer would’ve been enough: No. The hypothetical, which put opposition to interracial marriage on the same plane as opposition to same-sex marriage, was spurious. The court ruled against the school in Bob Jones University v. U.S. (1983) because all three branches of the federal government had a “firm national policy to prohibit racial segregation and discrimination in public education.” This consensus led the justices to conclude that “racially discriminatory educational institutions cannot be viewed as conferring a public benefit” and therefore aren’t entitled to tax-exempt status.

The court thus set a high bar for revoking tax-exempt status. The justices rightly understood that if tax-exempt status could be taken away for ordinary differences of opinion on politically charged issues, every church and nonprofit would live in fear that the next administration would pull the rug out from under it for not conforming to the prevailing views. The chilling effect on speech, belief and practice would be real and damaging.

When the court took up Obergefell in 2015, the government hadn’t reached such a consensus against the traditional view that marriage is as a union of a man and a woman. Congress had never recognized same-sex marriage in law, and until 2012, President Barack Obama publicly professed his belief in the traditional view.

The Respect for Marriage Act, which President Biden signed on Tuesday, puts the Bob Jones analogy to rest even as it affirms the legality of same-sex marriage. Now all three branches of government are on record affirming that belief in traditional marriage is “decent and honorable.” It isn’t only explicit in the legislation’s text, which protects tax-exempt status for “an otherwise eligible entity or person.” Every Supreme Court justice who joined the majority in Obergefell, every Democrat in Congress and President Biden himself have unanimously affirmed that believing in traditional marriage need not be based in bigotry.

The court’s opinion in Obergefell, written by Justice Anthony Kennedy, was joined by Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and Elena Kagan, all appointed by either Bill Clinton or Mr. Obama. It acknowledged that “many who deem same-sex marriage to be wrong reach that conclusion based on decent and honorable religious or philosophical premises, and neither they nor their beliefs are disparaged here.”

By calling the views of those who disagree with same-sex marriage “decent and honorable,” the court clearly brought those views into the realm of what might be called reasonable disagreement. People disagree about a lot of things in good faith. There are, however, some viewpoints that are so wrong that they’re undeserving of respect. Racial discrimination is the expression of one such view, and for that reason the court would never say that it is informed by “decent and honorable religious or philosophical premises.”

The Respect for Marriage Act uses language similar to Obergefell, if slightly less explicit, to affirm the reasonableness of traditional marriage. It states: “Diverse beliefs about the role of gender in marriage are held by reasonable and sincere people based on decent and honorable religious or philosophical premises. Therefore, Congress affirms that such people and their diverse beliefs are due proper respect.” As University of Virginia law professor Douglas Laycock points out, “diverse beliefs” doubtless includes the traditional conception of marriage. And while the Respect for Marriage Act protects both same-sex and interracial marriage, the text clearly distinguishes between the two by reserving “honorable and decent” treatment only to those who differ on the “role of gender in marriage,” not race.

Finally, Mr. Biden on Tuesday signed the Respect for Marriage Act into law, which gives us the trifecta. All three branches officially have recognized the reasonableness of traditional marriage.

With such a record, social conservatives should be able to take a deep breath and relax now that the angel of punitive taxation has passed them by. But it’s hard to forget the political rhetoric of the past few decades, which has seen progressives asserting that belief in traditional marriage is motivated by animus, bigotry and hatred. We’re told that limiting marriage to monogamous unions of a man and a woman is in effect the equivalent of banning interracial marriage.

Still, the law is the law. Social conservatives shouldn’t forget what Democrats agreed to in the Respect for Marriage Act. They shouldn’t let Democrats forget it, either.

Mr. Frost is director of public scholarship at Brigham Young University’s School of Family Life.