“HARD cases”, Oliver Wendell Holmes wrote in 1904, “make bad law”. But a ruling this week by the Supreme Court shows that cases featuring a tricky set of facts can, when the majority gets a little creative, make good law. In Heffernan v City of Paterson, New Jersey, the justices ruled 6-2 that a police officer who did a good deed for his ailing mother had a First Amendment right not to be demoted for appearing to engage in political speech when in fact he wasn’t expressing himself at all. A decade ago, Jeffrey Heffernan, a detective in Paterson’s police department, entertained a request from his bedridden mother to pick her up a yard sign supporting Lawrence Spagnola, her preferred candidate for mayor. (She had already been displaying a Spagnola sign in her front yard, but someone had stolen it.) Several of Mr Heffernan’s colleagues saw him procuring the sign at a Spagnola campaign site, and word quickly spread through the police department. Mr Heffernan’s boss and the chief of police were both supporting the incumbent mayor, Jose Torres, and looked askance on Mr Heffernan’s apparent support for his opponent. The next day, the chief of police told Mr Heffernan his recently won promotion to detective would be reversed, and he’d be back in his old job on walking patrol. The 20-year veteran cop’s good deed would be repaid with a demotion.

If Mr Heffernan had been picking up a sign for himself, or if he had asserted his personal support for the candidacy of Mr Spagnola (who happened to be his friend), his claim would have been vindicated without a visit to the Supreme Court. But Mr Heffernan insisted he had no involvement and no interest in the mayoral race and was acting merely as his mother’s agent in picking up the campaign material. Two lower courts said this fact disqualified him from protection under the First Amendment. No “First Amendment conduct” is entailed in the mechanical act of delivering a sign to a family member, the district court said. And the Third Circuit court of appeals agreed that “a free-speech retaliation claim” is valid “only where the adverse action at issue was prompted by an employee’s actual, rather than perceived, exercise of constitutional rights.”

Justice Stephen Breyer wrote for himself and five colleagues in reversing the Third Circuit and upholding the constitutional rights of the dutiful son. “The government acted upon a constitutionally harmful policy”, Justice Breyer announced, “whether Mr Heffernan did or did not in fact engage in political activity.” The Paterson police department’s motive “‘abridge[s] the freedom of speech’ of employees aware of the policy” and Mr Heffernan “was directly harmed, namely, demoted, through application of that policy.” To anchor this reasonable but somewhat counterintuitive ruling, the majority turned to Waters v Churchill, a 1994 case in which a hospital thought one of its nurses was merely gossipping when she was actually discussing hospital policy. In sacking her for insubordination, the court ruled, the employer did not violate the nurse’s constitutional rights because it reasonably believed her speech did not fall under the First Amendment umbrella. In Waters, Justice Breyer wrote, “the employer reasonably but mistakenly thought that the employee had not engaged in protected speech”. Heffernan presents an obverse set of facts: “the employer mistakenly thought that the employee had engaged in protected speech”. So if what mattered in Waters is “the employer’s motive...why is the same not true” in Heffernan? “In the law”, the decision concluded, “what is sauce for the goose is normally sauce for the gander.”

Justices Clarence Thomas and Samuel Alito dissented, noting that ‘“what is sauce for the goose’ is not “sauce for the gander”...when the goose speaks and the gander does not”. The police department’s “attempt” to violate Mr Heffernan’s right to speak or assemble “never ripened into an actual violation of [his] constitutional rights because, unbeknownst to the city, Mr Heffernan did not support Spagnola’s campaign.” It “may be callous” to demote a “dutiful son who aids his elderly, bedridden mother”, Justice Thomas wrote, “but it is not unconstitutional”.

In the majority’s eyes, letting the police officials off the hook for violating Mr Heffernan’s freedom of speech merely because a misperception fuelled their retaliation would have a chilling effect on public employees weighing whether to assert themselves politically. A ruling for the City of Paterson would “discourag[e] employees—both the employee discharged (or demoted) and his or her colleagues—from engaging in protected activities”. Whether based on facts or a flub, “the discharge of one tells the others that they engage in protected activity at their peril”.

Mr Heffernan’s monetary damages for his demotion await further legal proceedings. The majority opinion noted that “there may be a different and neutral policy prohibiting police officers from overt involvement in any political campaign” and that some evidence suggests that Mr Heffernan’s dismissal may have stemmed from such a non-ideological basis. “Whether that policy existed, whether Mr Heffernan’s supervisors were indeed following it, and whether it complies with constitutional standards” are all questions the lower courts will take up. But in revisiting Mr Heffernan’s claim, those courts are bound by the Supreme Court’s ruling that apparently political speech is as protected under the constitution as actual political advocacy. That’s a significant development extending a long line of cases that have broadened the zone of expression protected by the First Amendment.