WASHINGTON—Last week, the Supreme Court held that when the government mistakenly believes a person is exercising his free-speech rights, yet that person is, in fact, not exercising any rights at all, it still violates the First Amendment to punish that person for what officials thought he was doing. The Court’s conservative justices disagree.

Jeffrey Heffernan was a police officer in Paterson, New Jersey. Mayor Jose Torres was running for reelection against Heffernan’s friend, Lawrence Spagnola. Heffernan’s mother wanted to place a Spagnola campaign sign in her yard, but she asked Jeffrey to pick it up from the campaign office because she was ill.

Jeffrey did so. Another officer saw him go to the campaign office, pick up the sign, and talk with the campaign manager. Heffernan was later demoted from detective to a patrol officer walking the street.

Heffernan sued under 42 U.S.C. § 1983, the federal statute that a person uses to sue a state or local government for violations of rights granted by the U.S. Constitution or federal law. In Heffernan v. City of Paterson, the Supreme Court held 6-2 that demoting Heffernan violated his First Amendment rights.

Justice Stephen Breyer began for the majority, “With a few exceptions, the Constitution prohibits a government employer from discharging or demoting an employee because the employee supports a particular political candidate.”

Regarding the unusual facts of this case, the Court held:

When an employer demotes an employee out of a desire to prevent the employee from engaging in political activity that the First Amendment protects, the employee is entitled to challenge that unlawful action … even if, as here, the employer makes a factual mistake about the employee’s behavior.

Since Justice Antonin Scalia’s death, two conservative justices remain on the Supreme Court: Clarence Thomas and Samuel Alito. Justice Thomas dissented in Heffernan, joined by Justice Alito.

Thomas and Alito dissented because when Heffernan was picking up the campaign sign, he was only helping his mother, not actually engaging in political speech to support a political candidate (which all the justices agreed would have been protected speech under the First Amendment). Thomas wrote, “Federal law does not provide a cause of action to plaintiffs whose constitutional rights have not been violated.”

He elaborated: “For Heffernan to prevail on his § 1983 claim, then, a state actor must have deprived him of a constitutional right. Nothing in the text of § 1983 provides a remedy against public officials who attempt but fail to violate someone’s constitutional rights.”

Thomas criticized the actions of Paterson officials, but just because actions are distasteful does not make them illegal. He explained, “Demoting a dutiful son who aids his elderly, bedridden mother may be callous, but it is not unconstitutional.”

He then quoted a longstanding Supreme Court precedent that set the contours of federal civil-rights lawsuits brought under 42 U.S.C. § 1983, which held, “In order to seek redress through § 1983, … a plaintiff must assert the violation of a federal right, not merely a violation of federal law.”

Thomas used the example of a law authorizing police officers to pull over anyone on the road arbitrarily and without reason. Such a law would violate the Fourth Amendment, and any person pulled over could assert his Fourth Amendment rights. But if many officers did this and created traffic delays, the drivers who were delayed could not sue. They would have been injured by the government’s unconstitutional actions, but those action would not have violated any of their rights.

Heffernan marks the first time the Supreme Court has held that a person may sue for a civil-rights violation for a government action where the government official thinks he is violating that person’s rights, but did not actually do so only because the official was mistaken when the person was not engaging in legally protected activity.

Ken Klukowski is legal editor for Breitbart News. Follow him on Twitter @kenklukowski.