The U.S. Supreme Court over 30 years ago made clear that a reasonable police officer "should know the law governing his conduct."
Thus, when an officer arrests someone in clear violation of the law, his employer should not escape liability if the officer simply says “I thought I was acting lawfully.” All citizens are presumed to know the law. We should expect the same of police officers.
Indeed, if an officer's beliefs can immunize an unlawful arrest, then the innocent conduct of citizens may lead not only to arrests, but also to vehicle stops, searches, and interrogations—all arising from a citizen’s behavior or speech that (i) is not prohibited under any applicable law or (ii) is even expressly protected by the Constitution. We should not invite such civil liberties intrusions.
This question is now before the New Hampshire Supreme Court, and the ACLU of New Hampshire has addressed these issues in an amicus brief.
In the case Farrelly v. City of Concord, et. al., the plaintiff has asserted intentional tort claims against the City of Concord after Concord police officers arrested and prosecuted him pursuant to a statute, RSA 644:4, I(f), that had been struck down by the New Hampshire Supreme Court four years earlier in State v. Pierce, 152 N.H. 790 (2005) as violating free speech rights. The lower court held that the City was entitled to official immunity against the plaintiff’s claims simply because the police officers were unaware that the statute was unconstitutional at the time of the arrest despite being provided this information by the City.
As we argue in the brief, the lower court's decision to not examine whether the officers' conduct was objectively reasonable when measured against what would be expected of reasonably well-trained officers violated Part I, Article 14 of the New Hampshire Constitution. Indeed, the lower court's ruling, if adopted, would considerably restrict—if not outright eliminate—the ability of plaintiffs to seek redress for intentional torts in state courts against police officers and municipalities, including intentional torts arising out of clear violations of rights protected under the federal and state constitutions. Under the lower court's ruling, a municipality can obtain immunity for an intentional tort simply if the officer in question subjectively believed in the lawfulness of his or her actions, including relying on a statute that clearly has been held unconstitutional but has not been formally repealed. Such a rule would immunize, based solely on the officer’s subjective beliefs, even objectively improper conduct that no reasonably well-trained officer would ever think is appropriate. As we argue, an objective standard, on the other hand, recognizes the principle that it has always been the province of the courts, not law enforcement, to determine the reasonableness of an officer’s conduct in ascertaining whether immunity principles apply to violations of fundamental rights.