Jason Kessler, center, leads “Unite the Right” participants as they walk to Lafayette Square with a police escort on Sunday. (Jabin Botsford/The Washington Post)

As the D.C. region tallies the cost of a massive police effort to protect two dozen white supremacists who rallied on Sunday, some are questioning whether the extremist group received too many accommodations.

D.C. police and the mayor called the event a success — no injuries, one minor arrest — and said security measures were solely designed to physically separate white nationalists and counterprotesters with a history of violent clashes.

But those same methods included what appeared to observers as amenities — police escorts and a semiprivate Metro rail car to spirit the rally’s organizer, ­Jason Kessler, in and out of the District.

“All these police here, and they’re protecting them?” said ­Bethan Neal, who joined thousands of counterprotesters held by police at a distance from Kessler and his group. Neal is friends with the mother of Heather Heyer, the 32-year-old killed during Kessler’s first “Unite the Right” rally in Charlottesville last year. “They’re protecting that terrorist? It’s not right.”

The region’s ability to ensure a peaceful event may turn out to be a double-edged sword. Kessler, who thanked D.C. police and other law enforcement agencies for protecting his right to free speech, said it went so smoothly, he’d like to return. “Hopefully we’ll do more demonstrations in the D.C. area in the future,” he said.

Police called the rally a unique event that should not set a precedent for other small groups with incendiary messages to show up week after week and expect the same level of police protection. A spokesman for D.C. Police Chief Peter Newsham said the violent history between Sunday’s groups set it apart.

Police keep counterprotesters back during the “Unite the Right” rally in Lafayette Square on Sunday. (Jabin Botsford/The Washington Post)

“You need that number of officers to make sure no one gets hurt,” Newsham said.

The chief said that getting Kessler’s group safely out of Lafayette Square, where the rally was staged, required an “alternative plan” because the anti-fascist group known as antifa and other groups had gathered outside the rally’s entrance points. “There was a sense that tensions were rising,” the chief said.

Kessler and his group boarded a Metro train in Vienna and took it to Foggy Bottom. Despite assurances from the transit agency that they would not get a “private car,” reporters noted that Kessler’s group was in a rear Metro car with police escorts. Passengers were urged to board other cars, though reporters were able to get on the car with Kessler and his group.

After arriving in the District, they walked to the park, flanked by police. After the rally, they left amid an angry throng with the help of police, who appeared to use vans and diversion techniques designed to avoid concentrations of protesters, including antifa demonstrators gathered at White House entrance points.

Newsham, while not confirming details, called it “a well-executed plan.”

Most agencies from the District and Virginia were not immediately able to provide a detailed accounting of the costs to taxpayers. But it is clear that a massive amount of resources were used.

The District’s Metropolitan Police Department, with its 3,900 members, was on “full deployment” with overtime approved, authorities said.

Police agencies from Arlington and Fairfax counties in Virginia also helped, as did Virginia State Police, and large numbers of Metro Transit Police, U.S. Park Police and the Secret Service, along with the District’s Transportation and Public Works departments. Dump truck drivers, for example, parked rigs in streets to prevent motorists from using their vehicles to plow into crowds.

Last year in Charlottesville, Heyer was killed when a self-acclaimed white supremacist allegedly drove into an unprotected crowd, and two Virginia state troopers died when their helicopter crashed while observing the events on the ground.

Metro General Manager Paul J. Wiedefeld, in a statement, swatted away the notion that the white supremacists were given special treatment. Kessler’s group “rode a regularly scheduled Metro train that made all stops. . . . No passenger was turned away,” he said.

D.C. Council member Charles Allen (D-Ward 6), who leads oversight of public safety agencies, said he understood why officials were guarding white supremacists to prevent violence. “Just like everyone else, I hate seeing tax dollars and other things go to defend something I would spend a lifetime arguing against, but our police officers and law enforcement have a responsibility to make sure the city was safe during that event,” he said. “We certainly saw from a year ago when law enforcement doesn’t coordinate, when law enforcement doesn’t take it seriously, we saw what happened with devastating and deadly outcomes.”

But he said transportation officials seemed to cross a line by allowing white supremacists to board a public Metro train with a car essentially blocked off to the public. “Have we now set a precedent if one group feels their safety has come into question because of what they are espousing, they can now go onto Metro and have a private car essentially?” the council member said. “I think that’s a dangerous precedent. How does WMATA say no to the next group?”

Council member Robert C. White Jr. (D-At Large) also criticized Metro, saying it “broke the trust of WMATA employees and our residents.”

Mayor Muriel E. Bowser (D) oversaw the operation from a command center at police headquarters, after she abruptly decided to return from a previously scheduled four-day official trip to El Salvador. She and her chief of staff flew back to Washington on Sunday and returned Monday morning to complete the trip, costing taxpayers an additional $2,800.

The mayor’s return also seemed to be a matter of optics. Bowser’s office publicized photos of the mayor monitoring rallies, sitting in a seat reserved for a high-ranking D.C. Homeland Security official. Other mayors have been pilloried for being out-of-town during crises, including when Mayor Marion Barry (D) stayed in balmy Los Angeles for the Super Bowl in 1987 as a blizzard crippled the nation’s capital.

Anu Rangappa, Bowser’s spokeswoman, said Bowser decided to come back to D.C. after consulting with law enforcement and religious leaders ahead of the white supremacist rally.

“She understood there was consternation, and there was a lot of back-and-forth about how to best have leaders in the community to push back on this,” Rangappa said.

Though there were tense moments Sunday, the only arrest police reported was of a man they say punched an Ohio man for wearing a Trump hat. John Andrew Mulligan, 40, of Perkasie, Pa., a borough about 30 miles north of Philadelphia, was charged with assault and possession of a dangerous weapon. Police said he had a slingshot on him when he was arrested about 5 p.m. Sunday at New York Avenue and 13th Street NW.

A Superior Court judge ordered Mulligan released pending a hearing Sept. 24. He declined to comment as he left the courtroom.

Most counterprotesters left after Kessler had gone and a steady rain began to fall. But a group of antifa protesters marched through downtown, many angry with police over the protections given to Kessler, and briefly skirmished with officers at 13th and G streets.

Keith L. Alexander, Perry Stein, Peter Jamison, Marissa J. Lang and Hannah Natanson contributed to this report.