Let’s assume that the § 1983 plaintiff claims that she was arrested by the defendant police officer in retaliation for her exercise of free speech rights. The evidence shows that the arrest was supported by probable cause. Probable cause is a complete defense to a § 1983 Fourth Amendment false arrest claim. But is it also a complete defense to a § 1983 First Amendment retaliatory arrest claim?

In Lozman v. City of Riviera Beach, 138 S. Ct. 1945 (2018), the U.S. Supreme Court recently held, 8-1, that probable cause did not automatically defeat a §1983 First Amendment retaliatory arrest claim asserted against the city based upon its alleged enforcement of a policy of retaliation. Justice Anthony Kennedy wrote the opinion for the court. Justice Clarence Thomas was the sole dissenter.