Mayor Eric Johnson of Dallas announced on Friday that he had switched his party affiliation to become a Republican, saying that leaders in the Democratic Party had focused on “virtue signaling” and had not done enough to help residents of the nation’s cities.
The decision was surprising for its timing: Mr. Johnson was re-elected to a second term last year after running unopposed, and cannot run for a third. But the move appeared in line with how he had increasingly been positioning himself politically: At his second inauguration, Mr. Johnson was joined by Texas’s two Republican U.S. senators, Ted Cruz and John Cornyn.
Technically, the position of mayor in Texas is nonpartisan. But Mr. Johnson served in the Texas House of Representatives as a Democrat before he ran for mayor, and was long aligned with the party’s moderate wing. He pushed for major tax cuts in the city’s latest budget, and he has criticized Democrats in recent years for seeking to curtail police funding.
With his announcement, Mr. Johnson becomes one of the nation’s few big-city Republican mayors, and the only one to lead one of the 10 largest cities. He will have company nearby: Mattie Parker, the mayor of Fort Worth, is a Republican.
“American cities need Republicans — and Republicans need American cities,” Mr. Johnson wrote in an opinion essay in The Wall Street Journal on Friday, announcing his party switch.
“Too often, local tax dollars are spent on policies that exacerbate homelessness, coddle criminals and make it harder for ordinary people to make a living,” he wrote. “And too many local Democrats insist on virtue signaling.”
Mr. Johnson, who is Black, joins the Republican Party in Texas at a time when it has been trying to expand beyond its base of support in the state’s rural areas. The party is engulfed by an intramural fight over its direction, with its most conservative members accusing those who are seen as more moderate of being Republican in name only.
If Mr. Johnson’s goal is to run for higher office as a Republican, as some political analysts and elected officials said on Friday that they suspected, it was not clear that the mayor’s record could win over primary voters.
“It would be pretty difficult for him to change so dramatically to win over the Ken Paxton majority element of the Republican Party in Texas,” said Cal Jillson, a professor of political science at Southern Methodist University in Dallas, referring to the conservative Republican attorney general who recently survived an attempt by a competing wing of the party to impeach and remove him.
Still, many Republicans said on Friday that they were willing to welcome the mayor. Matt Rinaldi, the chairman of the Republican Party of Texas, wrote on the social media platform X that he was “thrilled” at the news of his switch. “We look forward to working with him to make Dallas better,” Mr. Rinaldi wrote.
“Welcome, Mayor!” Mr. Paxton said on X.
In his essay, Mr. Johnson said he would remain in office as mayor through the end of his current term in 2027.
Mr. Johnson had sought and received the backing of the Dallas business community for both his races for mayor, Mr. Jillson said, adding that doing so effectively cleared a path to re-election but often caused rifts with fellow Democrats on the City Council.
“He has always had difficulty creating a stable majority on the council,” Mr. Jillson said.
Unlike Houston, whose mayor also acts as city manager and directs municipal agencies, Dallas and most other Texas cities split the two roles, making the position of mayor more like that of a City Council president.
Mari Woodlief, a political consultant in Dallas who has represented Republicans and worked on Mr. Johnson’s re-election campaign, said the mayor’s party switch was “just formalizing the way he has been leading for the past couple of years.”
Still, the announcement caught many people in Texas off guard.
Sylvester Turner, the mayor of Houston, said he spoke with Mr. Johnson on Friday morning at an event in Austin, just a few minutes before the essay was published, and that Mr. Johnson did not mention it.
“I don’t think it speaks to any sort of shift in terms of party affiliation, or African American mayors,” Mr. Turner, who is Black, said in a telephone interview. “I think it has to be viewed as an individual making an individual decision. I don’t think it speaks to any sort of movement.”
He defended governance by Democrats in major cities, pointing to successes in Houston in lowering the number of murders and reducing street homelessness. “Mayors across the country, Democratic mayors, we are the boots on the ground,” he said. “We are responding to people’s needs.”
Mr. Turner added that though he could not say why Mr. Johnson had made the switch, the decision appeared to be a personal one. Or, he added, “maybe there’s something in the water.”
Dallas is a solidly Democratic city, and backed President Biden in the 2020 presidential election and the former congressman Beto O’Rourke in his failed bid for governor last year. The city’s City Council, also technically nonpartisan, is made up overwhelmingly of members who identify as Democrats. The last remaining Republican county commissioner in Dallas was defeated last year.
Mr. Johnson’s party switch “is an insult to the very voters who have gotten him to this point,” said Kardal Coleman, the chair of the Dallas County Democratic Party. “This is really a bait-and-switch.”
Adam Bazaldua, a Dallas city councilman, said Mr. Johnson’s tax policies were out of step with what the city’s voters wanted, and he criticized the mayor’s attacks on Democratic governance.
“That part is a hard pill to swallow,” Mr. Bazaldua said. “You can tout all day long the successes of our city, but you can’t ignore that it’s been run by Democratic councils. Our mayor is very quick to discuss stats of being the safest large city in the country. That was under our watch.”