BY NICOLE FLATOW POSTED ON OCTOBER 7, 2014

More than a month after Michael Brown was shot dead, protesters are still waiting for the grand jury to decide whether it will indict Darren Wilson.

But the first court ruling has been issued telling police to stand down when it comes to dealing with protesters. U.S. District Judge Catherine D. Perry held Monday that police can’t force protesters to “keep moving” — what some have dubbed the “five second rule.”

Police have developed a practice that prohibits protesters or others in protest zones from standing still. The upshot of this policy has been that even protesters who are peacefully praying, holding public gatherings, reporting the news, and informing others of their rights have been corralled into assembly lines and told they will be arrested if they don’t “keep moving.” Officers have also threatened protesters for walking too slowly, or who walk back and forth within a limited space. And they have followed through on those threats. After one individual was arrested under the policy, citing a “failure to disperse,” an officer told an NBC News reporter: “He was supposed to keep moving, just as you’re supposed to keep moving.”

The net effect, Judge Perry concluded, was that it prevented protesters from exercising their right to “peacefully assemble on the sidewalk.”

“The rule provided no notice to citizens of what conduct was unlawful, and its enforcement was entirely arbitrary and left to the unfettered discretion of the officers on the street,” Perry held. She issued a preliminary injunction, meaning police must halt their practice pending a permanent ruling.

Plaintiff Mustafa Abdullah works for the American Civil Liberties Union, and part of his job is to talk to protesters about their rights and how to avoid arrest. On his first attempt to get an injunction against the “keep moving” practice, Judge Perry denied the request, because officers said they had designated particular areas where protesters could stay in place and gather. But after that ruling, Abdullah was told by multiple officials that they knew of no such safe protest zone. Eventually, a “Protester Assembly Zone” was established, but it was isolated from the restrooms, water access, and the media stage. And protesters continued to tweet that they were being threatened with arrest while standing in that designated area if they did not keep moving, or did not move after standing still for five seconds — quickly and in one continual direction, in some instances.

Perry held on the second motion that the policy violated protesters’ First Amendment and due process rights because it was not targeted at individuals who were committing crimes or engaging in violent acts, or even crowds with some individuals committing those offenses.

“Vague rules that are applied in a haphazard fashion tend to increase community tension,” said Tony Rothert, legal director of the ACLU of Missouri.

Hundreds of protesters and journalists have been arrested since Brown was shot, some in just the past few days for “failure to disperse.”