Law enforcement authorities are monitoring plans by supporters of former president Donald Trump to rally outside the U.S. Capitol later this month to argue that the hundreds of people charged in the Jan. 6 insurrection are political prisoners, an assertion that has exploded beyond far-right rallying cries and into mainstream conservatism.

Look Ahead America, a nonprofit group founded and led by Matt Braynard, a former Trump campaign operative, is planning a “Justice for J6” rally on Sept. 18 to bring its message to Washington. Braynard’s followers believe many of the more than 570 people who have been charged with federal crimes in the attack were nonviolent and “reasonably believed they had permission” to enter the Capitol, according to a Jan. 29 letter Braynard sent to the Department of Justice and FBI. Braynard’s letter demands prosecutors drop all charges.

Braynard’s group requested to hold its rally at Union Square, the public park by the Capitol Reflecting Pool, according to a permit application his group submitted to the U.S. Capitol Police Board and provided to The Washington Post. Although local authorities have not provided crowd estimates, Look Ahead America estimates that 700 people will attend — up from an earlier estimate of 500 in a previous permit application. Plans for a counterprotest began to circulate online this week.

D.C. police, Capitol Police and U.S. Park Police met with the group on Wednesday so that the group could answer questions about its permit request. The conference call seemed to be the next phase in the process, but authorities have not yet granted a permit for the event, Kimmie Gonzalez, the group’s director of government affairs who attended the meeting, said in an interview Thursday.

The permit application described the event as “a peaceful demonstration of our First Amendment rights.”

The planned rally comes as the city is still recovering from three attacks in eight months in the nation’s capital. A violent mob stormed the seat of the U.S. government on Jan. 6, disrupting Congress from confirming President Biden’s election victory and resulting in the deaths of five people. In April, a man rammed his car into a barricade outside the building, killing a Capitol police officer, and last month, a man threatening that he had a bomb parked a truck near the Capitol and demanded to speak to Biden.

During the Jan. 6 riot, Trump supporters brawled with police, broke windows, threatened to harm lawmakers and stormed through the white pillared building. However, groups such as the far-right Proud Boys and Oathkeepers quickly organized to raise money for their members who faced federal charges, said Heidi Beirich, co-founder of the Global Project Against Hate and Extremism and the former director of intelligence at the Southern Poverty Law Center.

They embraced a counternarrative, that many of those at the riot were simply swept away in a moment of nonviolent political protest. This was soon a talking point among Republican lawmakers aiming to downplay the events of Jan. 6, including Rep. Andrew S. Clyde (R-Ga.) who said footage of the riot that day appeared to be “a normal tourist visit.

Braynard has held rallies for Jan. 6 arrestees before, including a small showing in July outside the D.C. Central Detention Facility where about 100 demonstrators gathered and carried signs that said “protests are not insurrections” and “patriots are not terrorists.” D.C. jail officials have also turned away Republican members of Congress — Reps. Matt Gaetz (Fla.), Marjorie Taylor Greene (Ga.), Paul A. Gosar (Ariz.) and Louie Gohmert (Tex.) — who showed up in July demanding to inspect the treatment and conditions of those detained on charges related to the Jan. 6 riot.

Those representatives all opposed a probe of Jan. 6 and were part of the group of 21 House Republicans who voted against awarding the Congressional Gold Medal to all police officers who responded that day.

“It was like wildfire. This went from the fringes to the GOP to Fox very, very quickly,” Beirich said. “Most of conservative America seems to think that January 6th was no big deal.”

The Proud Boys, a far-right group with a history of violence, has told its members on social media posts not to attend this month’s rally, citing concerns that they would be arrested. Some ranks of the Proud Boys have splintered since its leader, Henry “Enrique” Tarrio, was revealed to have been an FBI informant.

“We aren’t going and you shouldn’t either because errbody going to jail. Sounds like bait,” the Proud Boys wrote in a message. This does not necessarily mean members of other factions will not attend.

“I was at the 6th and we got played,” one user wrote in another message.

On the recent conference call with local officials, Gonzalez said she was asked about the purpose of the event, the number of attendees, vendors and whether Look Ahead America was aware of any other “groups” planning to attend.

“Our event is a Rally Against Political Persecution to bring awareness and attention to the unjust and unethical treatment of nonviolent January 6 political prisoners who are being denied their basic rights as afforded by the Constitution,” a description of the event reads on a permit application. “The event will include the saying of the Pledge of Allegiance, songs of patriotism, prayer, guest speakers, and the showing of a video. We will be using this time to make our voices heard in asking that all charges be dropped for nonviolent detainees and they be released from solitary confinement.”

Look Ahead America, Gonzalez said, has “no relationship” with the Proud Boys and the Oathkeepers. But she said that she has heard from state-level volunteer coordinators for the group’s “Satellite Rallies to #FreePoliticalPrisoners,” which occurred this summer in Arizona, Texas, Georgia, Florida and New Jersey, that members of the Proud Boys have showed up to some rallies.

However, there was “zero incident,” she said. “They came to listen. There was no attack, there was no violence, there was no incidents, no altercations, no anything. … everyone came in peace.”

Still, local law enforcement is preparing for the event.

D.C. police will be “fully activated” on Sept. 17 and 18, spokesman Dustin Sternbeck said. This means all officers must work those days, a routine request ahead of anticipated large gatherings.

“While there’s no indication this demonstration is to be outside of the routine for us, we will allocate resources to be able to respond if necessary,” Sternbeck said. “Again our priority is the safety of all and we will continue to monitor on an ongoing basis.”

Capitol Police are also “closely monitoring” plans for the rally, Capitol Police Chief Tom Manger said in a statement Wednesday. Capitol Police declined to comment on reports that there are considerations to reinstall the fencing that was erected around the building after Jan. 6.

When the perimeter fencing was removed in July, authorities noted that the Architect of the Capitol can “expeditiously reinstall the temporary fencing should conditions warrant,” according to a memo sent to lawmakers.

“After January 6, we made Department-wide changes to the way we gather and share intelligence internally and externally,” Manger said in a statement. “I am confident the work we are doing now will make sure our officers have what they need to keep everyone safe.”

Capitol Police have declined to share more information on the status of permits for the event or other security measures.

Capitol Police have requested support from neighboring police departments in Arlington and Montgomery counties on the day of the planned rally, according to those departments.

A federal law enforcement official also said the FBI was aware of online chatter about the event, and said Capitol and D.C. police were discussing extra security precautions. Though many similar events in the past have come and gone without incident, law enforcement has generally eyed them more warily since Jan. 6.

Del. Eleanor Holmes Norton (D), D.C.’s nonvoting delegate in the House, said any reports that Capitol security officials had been discussing whether to again erect the Capitol perimeter fencing concerned her.

She said she understood the need for the fence in the case of imminent danger to the Capitol. But she said without more information about potential threats, the fence should not be used to preemptively block people from protesting on Capitol grounds, no matter their views. In the months after Jan. 6, she had been among the most outspoken members of Congress advocating to remove the fence and not to restrict access to the “people’s house.”

“Of course we’ve said that when there are dangers to the Capitol, fencing will go up,” said Norton, a former First Amendment lawyer. “But these people are engaged in a demonstration, and you’re allowed to go on the Capitol grounds to indicate your views. So the fencing could raise First Amendment concerns if it kept people from going onto the Capitol grounds.”

Meagan Flynn, Matt Zapotosky, Justin George, Rachel Weiner and Peter Hermann contributed to this repot.