After the infamous demonstrations in Charlottesville, Va., by white supremacists last August, a small town in mid-Tennessee was targeted for similar demonstrations. But the organizers canceled at the last minute.

The groups started in Shelbyville the morning of Oct. 28 and were supposed to go to Murfreesboro in the afternoon. Instead, demonstrations in Murfreesboro were called off, with leaders citing a “lawsuit trap.” There were no reported injuries or property damage at either location, and only one misdemeanor arrest in Shelbyville, compared to three deaths and 34 injuries in Charlottesville.

News reports at the time credited a large presence of counter protestors, but city officials said Thursday it was something much more mundane: a law on the books since 1796.

Further, every single state has a similar type of law, according to a new report, and its authors think they can effectively prevent another Charlottesville – if states know how to use them.

Officials at the Institute for Constitutional Advocacy and Protection (ICAP) at Georgetown University Law Center contacted the city of Murfeesboro in mid-October, as officials were preparing for a “White Lives Matter” rally led by League of the South, a neo-Confederate and white supremacist organization. City officials planned to designate certain areas for protest and counter protest groups, but were struggling with other ways to prevent violence.

“It was good timing,” said Adam Tucker, the assistant city attorney at Murfreesboro. “At the time, we felt law enforcement had developed a good plan ... but we were still grappling with how to prevent violence between the groups outside the restricted areas.”

Georgetown officials, including Mary McCord, senior litigator at ICAP, pointed city officials to one constitutional provision and two statutes to help police tamp down violence without quashing free speech. The Tennessee constitution mandates that military actors submit to civil authorities, a provision that has remained unchanged since 1796 and exists in some form in all state constitutions except New York’s and Georgia’s. Two additional statutes in Tennessee prohibit paramilitary activity and “false assumption,” meaning the unauthorized wearing of military uniforms or otherwise assuming the role of a peacekeeper under false pretenses.

Paramilitary activity was obvious in Charlottesville, McCord said. She cited groups wearing matching uniforms, carrying weapons such as clubs and bats in addition to firearms, using pre-baked slogans and coordinating violent movements orchestrated by “commanders.”

“They had a strategy to provoke counter protestors to engage in initial acts of violence so they could retaliate with more severe violence and claim self-defense,” McCord said. “That is a military tactic.”

Tucker said Murfreesboro then used those laws in writing the protest permit for the League of the South, particularly citing the ban on paramilitary activity and clarifying to the group that they would be liable for any paramilitary – unofficial military – activity by their group members in any area that could be deemed part of the event.

Tucker said he believes that is what prompted a tweet by Brad Griffin, a leader in League of the South whose account under the name Hunter Wallace has since been suspended by Twitter, which said, “Had some intel Murfreesboro was a lawsuit trap. Not worth the risk.” Murfreesboro had expected around 200 white supremacist protestors; only about 20 showed up and quickly left.

“I believe they not only felt they couldn’t intimidate counter demonstrators as they did in Charlottesville, but also that they doubted their ability to control their members,” Tucker said. “With that language in writing in the permit, they would’ve been at high risk for a lawsuit.”

George Selim, who led a task force on countering violent extremism at the Department of Homeland Security and is now at the Anti-Defamation League, said white supremacists and other extremists groups tend to not be cowed by counter protestors; if anything, they’re emboldened. It’s much more critical for cities and states to understand their legal tools for countering violence, and to set permit conditions accordingly, he said.

McCord and her fellow researchers found four types of laws that states can use to combat the next Charlottesville, the last being a prohibition against private militias without permission by the state government. There are 48 states with constitutional provisions requiring subordination of the military, 28 states that prohibit private militias, 25 states that ban paramilitary activities and 12 states with false assumption statutes.

The report was sent to all 50 state attorneys general; McCord said a few have already written back with their thanks. It’s likely there will be more attempts at demonstrations: Between September 2016 and January 2018, ADL recorded 346 incidents of white supremacist propaganda – fliers, stickers, banners, and posters – appearing on college and university campuses. Those incidents more than tripled in 2017, according to an ADL report on murder and extremism.

“The white supremacist murders included several killings linked to the alt right as that movement expanded its operations in 2017 from the internet into the physical world—raising the likely possibility of more such violent acts in the future,” the report states.

Jason Kessler, a white nationalist who organized the 2017 Charlottesville rally, has posted to his website a permit application for another such rally in Charlottesville on Aug. 11 and 12. The idea of an anniversary protest has been popular in white nationalist circles, though Charlottesville has not yet approved the permit submitted in November.

“There was all this talk before Charlottesville with this resigned tone, that law enforcement couldn’t do anything due to free speech protections,” McCord said. All four types of state laws do nothing to infringe on speech, but specifically prevent the type of paramilitary action that made Charlottesville so violent, she said.