During a recent appearance on CBS' The Late Show, Pete Buttigieg responded to recent criticism by two Supreme Court justices on marriage equality.

Justice Clarence Thomas wrote the voluntary statement and Justice Samuel Alito co-signed.

In the statement, the justices criticize Obergefell, the 2015 high court ruling that found gay and lesbian couples have a constitutional right to marry, as damaging to religious liberty.

(Related: Thomas, Alito: Same-sex marriage ruling has “ruinous consequences for religious liberty.”)

“I'm tired of the existence of my marriage, my family being up for debate,” Buttigieg told host Stephen Colbert. “This question was settled. And when it was, that was a step forward in this country. And the idea that these justices who ascribe to a judicial philosophy, or claim to, that's about precedent and about not legislating from the bench, to now, as I understand it between the lines, threatening marriage equality, it's just a reminder of what's at stake in this election.”

Buttigieg said that “the world became a lot better ... for a lot of people” when gay couples gained the right to marry.

“It's not the time to turn backwards,” he added.

Buttigieg, who is promoting his latest book, Trust: America's Best Chance, came out gay before being elected to a second term as mayor of South Bend, Indiana. His presidential campaign made history when he became the first openly gay presidential candidate to win delegates during the Democratic primary. Since dropping out of the race, Buttigieg has endorsed former Vice President Joe Biden.

Buttigieg, 38, married Chasten Buttigieg in 2018.