prosecutor to bring charges that would not have been initiated without his urging.” Id., at 262. Noting that inquiries with respect to probable cause are commonplace in criminal cases, the Court determined that requiring plaintiffs in retaliatory prosecution cases to prove the lack of probable cause would help “bridge the gap between the nonprosecuting government agent’s motive and the prosecutor’s action.” Id., at 263.
The City’s argument here is that, just as probable cause is a bar in retaliatory prosecution cases, so too should it be a bar in this case, involving a retaliatory arrest. There is undoubted force in the City’s position. Reichle, 566 U.S., at 667–668. There are on average about 29,000 arrests per day in this country. Dept. of Justice–FBI, Uniform Crime Report, Crime in the United States, 2016 (Fall 2017). In deciding whether to arrest, police officers often make split-second judgments. The content of the suspect’s speech might be a consideration in circumstances where the officer must decide whether the suspect is ready to cooperate, or, on the other hand, whether he may present a continuing threat to interests that the law must protect. See, e.g., District of Columbia v. Wesby, 583 U.S. ___, ___ (2018) (slip op., at 10) (“suspect’s untruthful and evasive answers to police questioning could support probable cause” (internal quotation marks omitted)).
For these reasons retaliatory arrest claims, much like retaliatory prosecution claims, can “present a tenuous causal connection between the defendant’s alleged animus and the plaintiff ’s injury.” Reichle, 566 U.S., at 668. That means it can be difficult to discern whether an arrest was caused by the officer’s legitimate or illegitimate consideration of speech. Ibid. And the complexity of proving (or disproving) causation in these cases creates a risk that the courts will be flooded with dubious retaliatory arrest suits. See Brief for District of Columbia et al. as Amici Curiae 5–11.
