Austin Mayor Steve Adler endorsed Pete Buttigieg for president Sunday, introducing a fellow mayor he calls his mentor at the official launch of the Hoosier's presidential campaign Sunday in his hometown of South Bend, Ind.

In choosing the 37-year-old Buttigieg as a role model, Adler said, "the irony was not lost on me that I was looking up to someone that was shorter than I was, that was younger than me, a mayor of a smaller city than mine and from a different part of the country, a mayor whose community has challenges different from mine."

"But I was looking for and I found in Mayor Pete a true executive, a mayor whose skills and talents transcend all of that," Adler said. "Mayor Pete is a mayor’s mayor. He is a mayor among mayors. I am standing here today with other mayors because we know something that this country needs to know, and we are in a unique position to know it. We can answer the question that many in America are asking. Yes, America, Mayor Pete really is that special."

Adler's endorsement was especially notable because there are two Texans — former U.S. Rep. Beto O'Rourke of El Paso and former San Antonio Mayor Julián Castro — already seeking the Democratic nomination for president. Buttigieg's fast-rising candidacy has especially complicated O'Rourke's play as an attractive young, white, male candidate from a red state.

Ever since an impressive performance at a March 10 CNN Town Hall at South by Southwest, Buttigieg has been on a tear, winning favorable press and raising more than $7 million in the first quarter of the year. That's less than O'Rourke's $9.4 million, but very good for someone who was a virtual unknown nationally a couple of months ago. Buttigieg is also hurtling past O'Rourke in polls in early voting states of Iowa and New Hampshire. He has pushed to the front of the second tier of candidates after former Vice President Joe Biden, who has not yet announced his candidacy, and U.S. Sen. Bernie Sanders of Vermont, who lost his bid for the nomination in 2016.

Adler's backing also will increase the intensity of competition in the Texas Democratic presidential primary next March. Austin and its environs will play an outsized role where O'Rourke's success will likely hinge. Former Houston Mayor Annise Parker also tweeted from the Buttigieg event: "The energy in South Bend is electric."

Adler was one of three mayors, along with Nan Whaley of Dayton, Ohio, and Christopher Cabaldon of West Sacramento, Calif., to speak at Buttigieg's rally. But it was Adler who had the high-profile honor of introducing Buttigieg as "the next president of the United States."

That is something Adler didn't say when he spoke at O'Rourke's March 30 rally in Austin to officially kick off his presidential campaign. Adler told the Statesman on Sunday that his role at that event was to welcome O'Rourke to Austin as mayor, not to endorse his candidacy.

Adler said he had not yet made up his mind to endorse Buttigieg at that point, but as he watched Buttigieg rise in popularity, he said he realized that he was in a position to help America know and appreciate his friend and colleague.

"There are several good people that are running in there. Beto's a really good guy. Julián is a good guy," Adler said. "But as I was watching the campaign develop and knowing as I do just how unique Pete really is, it became more and more apparent that given the vantage point I have, being able to see him the way that I've seen him, validating that became something that just became important for me to do."

Adler and his wife, Diane Land, attended Buttigieg's wedding to Chasten Glezman, a junior high school teacher, last June, and Buttigieg has been a guest at Adler's home on several occasions, including during his recent visit for South by Southwest.

If elected, Buttigieg would be the first openly gay man — and the youngest person — to become president.

But Adler's introduction stressed more classic virtues.

"Wouldn't it be great if we had a president who was thoughtful, rational, intelligent, deliberate, or simply told us the truth?" Adler asked the crowd. "Wouldn't it be great if we had a president like Pete?"