A judge for the US District Court for the Eastern District of Missouri issued an order [text, PDF] Wednesday placing restrictions on how the St. Louis Metropolitan Police Department may interact with protesters.
The order states that the City of St. Louis will not give the police the authority or discretion to declare an unlawful assembly against protesters unless they are posing an imminent, violent threat. They also may not declare an unlawful assembly for the purpose of punishing people simply for exercising their right to protest, nor may they use chemical agents against those people.
The order also prohibits the use of chemical agents without probable cause to arrest the person they are using it against. It further clarifies that chemical agents may only be used after giving clear and unambiguous warnings and giving people enough of a chance to comply with law enforcement commands. Chemical agents may also not be used to disperse groups of protesters without giving warnings and an ample amount of time for groups to leave the area.
This decision is a result of a lawsuit [complaint, PDF] that the American Civil Liberties Union (ACLU) filed against the city of St. Louis for unconstitutional police conduct. In September people gathered to protest [WP report] the acquittal of a white former police officer who killed a black suspect. During these protests, officers used chemical weapons [ACLU website] against protesters, as well as unlawfully detained them.