Last month, the U.S. Supreme Court agreed to hear Lozman v. City of Riviera Beach, Florida. Lozman presents a conflict between a longstanding principle of Fourth Amendment law and an equally venerable strain of First Amendment law. This conflict has divided lower courts and is critical to police and municipalities in today’s environment of heightened political protests.

The question is whether a person who sues, claiming that he or she was arrested in retaliation for exercising free speech rights automatically loses if the defendant can show that there was probable cause to arrest the plaintiff for any crime. Fourth Amendment principles say yes, because the test for an unlawful arrest depends solely on the objective circumstances at the time of the arrest: objective probable cause to arrest the person for any crime always defeats a claim for unconstitutional arrest regardless of either the subjective motives for the arrest or the specific crime for which the person was arrested. But First Amendment principles say no, because in the First Amendment context, the Supreme Court scrutinizes the subjective motives of state actors and rules based on whether a state actor intended to suppress protected speech, not whether speech suppression occurred.

In Lozman, plaintiff Lozman, a longstanding and outspoken critic of the defendant city, was arrested for disorderly conduct after he refused to yield the podium and stop denouncing city policy at a city council meeting. The state’s attorney declined to prosecute the case, and Lozman was released. Lozman sued, claiming that he was arrested in retaliation for exercising his First Amendment rights to free speech. At trial, he introduced extensive evidence of this retaliation, including a statement from one council member shortly before the arrest that the city needed to “intimidate” Lozman. Nevertheless, Lozman lost. The U.S. Court of Appeals for the Eleventh Circuit looked at the case through a Fourth Amendment lens and held that because Lozman’s conduct gave probable cause to arrest him from disorderly conduct, his evidence of the city officials’ retaliatory motive didn’t matter.

Although several federal courts nationwide agree with the Eleventh Circuit, others have concluded the exact opposite. Here in Illinois, the most recent Seventh Circuit case on point ruled that because the courts were divided, the law was not clear, and therefore Chicago police officers who arrested a prominent anti-war protestor for disorderly conduct, with probable cause to do so, were entitled to qualified immunity regardless of their motives. But once the Supreme Court decides Lozman in the spring of 2018, the law will be clear. And the moment the law is clear, every municipality and police department in Illinois should study that law carefully in order to properly train and instruct their officers.