NEW YORK (AP) — A divisive debate over same-sex marriage animated the 2004 presidential election as voters across the country approved constitutional amendments banning such unions. Sixteen years later, with those bans invalidated and his husband by his side, Pete Buttigieg became the first openly gay man to become — however briefly — a leading presidential candidate.

Buttigieg fell short of his goal to win the Democratic nomination and defeat President Donald Trump. But his candidacy will likely be remembered as an example of the remarkable advances made by LGBTQ Americans in their quest for equality and acceptance.

The former mayor of South Bend, Indiana, suspended his campaign Sunday, saying he saw no path to victory after a poor showing among black voters left him a distant fourth in South Carolina’s primary. But activists hailed Buttigieg as a trailblazer and an inspiration for what they hope will be future waves of LGBTQ candidates at every level of U.S. politics.

“Pete’s candidacy represents a revolution in American politics, forever transforming what is possible for an LGBTQ candidate and making clear America will elect an openly LGBTQ president,” said Annise Parker, a former mayor of Houston. She now heads the LGBTQ Victory Fund, which recruits and supports LGBTQ candidates for political office.

“Pete spoke in small-town restaurants in Iowa, held rallies in New Hampshire and battled it out on the presidential debate stage,” Parker said. “He inspired LGBTQ youth to come out in valedictory speeches, to attend their first Pride parade, and to believe America has a place for them.”

While there have been gay governors and members of Congress, Buttigieg resonated with some voters for his potential to win the nation’s highest office. He battled Bernie Sanders to a virtual first-place tie in the opening caucuses in Iowa and finished just one percentage point behind Sanders in New Hampshire before slipping to third in Nevada. He was expected to endorse fellow moderate Joe Biden on Monday, according to two people familiar with Buttigieg’s decision who were not authorized to speak publicly and spoke to The Associated Press on condition of anonymity.

While he often campaigned with his husband, Chasten, and was comfortable discussing his sexual orientation, it was rarely a focus of his own speeches or of commentary from his critics or opponents.

“The fact that Pete was gay didn’t really come up that much, which itself was an important marker,” said Richard Socarides, a former Clinton White House adviser on gay issues. “It’s such an angry, intolerant time. But Pete’s campaign proved that Americans are still capable of tolerance and accepting of differences.”

One exception came in mid-February, when Rush Limbaugh said on his radio show that “America’s still not ready to elect a gay guy kissing his husband on the debate stage.”

Buttigieg, in response, held up his marriage as a contrast with Trump, who has been accused of infidelity and sexual assault — allegations he has denied.

“I mean, I’m sorry, but one thing about my marriage is it’s never involved me having to send hush money to a porn star after cheating on my spouse with him or her,” Buttigieg said. “So they want to debate family values? Let’s debate family values.”

Still, Buttigieg was a controversial figure in some LGBTQ circles. As a white man with a Harvard degree, he acknowledged enjoying privileges that aren’t extended to women, people of color and the poor.