Lawyers representing many of the more than 200 people charged with rioting in Washington, DC, on Inauguration Day are arguing the cases should be dismissed, and they warn if they aren’t, the outcome would risk chilling future First Amendment–protected protests.

At a marathon court hearing on Thursday, defense lawyers framed the fight over the Jan. 20 cases as critical for defining when people could face criminal charges for protesting in the nation’s capital. Although technical at times, the arguments had an underlying theme: If the indictment were allowed to stand, it would put people exercising their free speech rights at a higher risk of arrest.

The lead prosecutor in the case, Assistant US Attorney Jennifer Kerkhoff, argued Thursday that many of the challenges to the indictment were fact-based — who did what on Jan. 20 — which were questions for a jury to decide, not the judge. She said the indictment on its face laid out facts that supported charges that the defendants willfully incited and engaged in a riot. According to court filings, there was more than $100,000 in property damage.

A person could participate in a riot even if they were not the one to throw a rock or break a window, Kerkhoff said.

“It is the group … the group that is the danger, the group that is criminal,” she said.

Police arrested 234 people in connection with demonstrations that turned violent in downtown Washington during President Trump’s inauguration. Store and car windows were smashed as the demonstrators, many dressed in black and wearing face masks, marched through the streets. The majority of arrests were made on the scene.

There are 197 cases pending; 17 people have pleaded guilty and prosecutors have dropped 20 cases so far.

Defense lawyers argued Thursday that the indictment was legally deficient and unconstitutional. Attorney Joshua Shiffrin, who spoke on behalf of a large group of defendants seeking dismissal of the indictment, said that the government’s legal theories underpinning the charges were “aggressive” and “untested.”

Several defense lawyers separately argued for the judge to order the government to disclose instructions that prosecutors gave to the grand jury that returned the indictment. Grand jury proceedings are secret, but defense lawyers argued there were errors in the indictment that raised concerns prosecutors gave the grand jury bad legal information. The government on Thursday agreed to dismiss one count of the indictment that was based on a defunct version of a law against assaulting police officers.

District of Columbia Superior Court Judge Lynn Leibovitz did not rule from the bench.

With 197 defendants pending, almost all of whom have their own lawyer, the case has been a logistical challenge for the court. Leibovitz heard arguments on Thursday over more than four hours from a series of lawyers. Some argued on behalf of a group of defendants, while others only argued for their clients. The courtroom and an overflow courtroom were packed with attorneys, defendants, observers, and reporters.

The judge asked a number of questions about two cases from the 1960s and one from 2009 that addressed the standards for prosecuting rioting offenses under DC law. Given the rarity of rioting cases, lawyers on both sides acknowledged there was limited precedent to draw on.

Defense attorney Veronice Holt argued broadly that the indictment should be dismissed under the First Amendment’s free speech protections. She said that although the indictment referred to all of the defendants as the “rioting defendants,” it attributed specific acts of destruction to unspecified “individuals.” No individual rioting defendant was accused of engaging in acts of violence, she said.

The two 1960s-era cases discussed at length, US v. Matthews and US v. Jeffries, spelled out jury instructions used in rioting cases that to find a defendant guilty of rioting, they had to find that they were aware of the rioting and willfully participated. Leibovitz asked Holt why those instructions wouldn’t satisfy concerns about people engaging in lawful protest activity.

Holt said the government had alleged that people were criminally liable because they did not leave when others around them engaged in criminal activity. If leaving was what was required, Holt said, that would be an “unacceptable prior restraint” of First Amendment free speech rights.

The arguments delved into the nuances of the charges, including what the government would have to prove to show that someone incited a riot, as opposed to engaged in one — the indictment includes separate charges for inciting and engaging — and whether the government could charge someone with being part of a conspiracy if the underlying offense — in this case, rioting — already included a requirement that multiple people be involved.

Shiffrin argued that incitement meant the use of words directed at a certain group of people to encourage certain behavior, which was separate from participation in a riot. There were no message-oriented allegations in the indictment, he said.

And on the question of whether the government met its burden for charging people with engaging in a riot, Shiffrin argued that the indictment had to allege facts that showed the defendants acted with intent to further the illegal conduct of the group, which he said it did not do.

Leibovitz pressed Shiffrin to offer examples of conduct that would clearly show that a person was participating in a riot.

What if they were cheering on others, she asked. Cheering wouldn’t be enough, Shiffrin replied. The government had to show that a person intended to incite behavior that created a “grave risk” of injury or property damage, he said.

Kristin Robinson, a lawyer representing two defendants, said her clients were in a different position than many others because there was evidence they didn’t arrive on the scene until after much of the marching and property destruction described in the indictment — conduct that was cited to support the rioting charges — took place. Robinson argued that this was proof the grand jury wasn’t presented with information specific to her client, in violation of their constitutional rights.

Kerkhoff responded that Robinson’s argument assumed the grand jury didn’t evaluate evidence that favored her clients in deciding whether to indict them, and that there was evidence Robinson’s clients were looking for the rioters and moved to join them.

Kerkhoff argued against revealing the instructions given to the grand jury. She said that speculation by defense counsel wasn’t enough to go behind the secret grand jury proceedings.

Michael Satin, the defense lawyer who made the primary arguments in favor of seeing the grand jury instructions, said that he had never made this type of request before, but these cases presented novel circumstances and legal questions.

“I think it’s important to realize just how unusual this case is,” he said.