WASHINGTON — The Supreme Court unanimously ruled on Thursday that elected bodies do not violate the First Amendment when they censure their members.

The case concerned David Wilson, a former elected trustee of the Houston Community College System and an energetic critic of its work. In addition to airing his concerns in interviews and on a website, Mr. Wilson sued the system’s board, orchestrated robocalls and hired private investigators to look into whether another trustee had lied about where she lived.

He was, a federal appeals court judge wrote in a dissent, a “gadfly legislator.”

In 2018, Mr. Wilson’s fellow board members issued a formal verbal reprimand against him in a censure resolution. “The board finds that Mr. Wilson’s conduct was not only inappropriate, but reprehensible, and such conduct warrants disciplinary action,” its resolution said.

He sued, saying the punishment violated the First Amendment by retaliating against him for things he had said.

Justice Neil M. Gorsuch, writing for the court, said Mr. Wilson misunderstood the nature of the national commitment to free speech.

“In this country,” he wrote, “we expect elected representatives to shoulder a degree of criticism about their public service from their constituents and their peers — and to continue exercising their free speech rights when the criticism comes.”

The board also took more concrete actions against Mr. Wilson, like making him ineligible for reimbursement for work-related travel. But those punishments were not before the court, Justice Gorsuch wrote.

“The only adverse action at issue before us is itself a form of speech from Mr. Wilson’s colleagues that concerns the conduct of public office,” Justice Gorsuch wrote. “The First Amendment surely promises an elected representative like Mr. Wilson the right to speak freely on questions of government policy. But just as surely, it cannot be used as a weapon to silence other representatives seeking to do the same.”

Justice Gorsuch added that historical practices cut against Mr. Wilson’s position in the case, Houston Community College System v. Wilson, No. 20-804.

“Elected bodies in this country have long exercised the power to censure their members,” he wrote. “In fact, no one before us has cited any evidence suggesting that a purely verbal censure analogous to Mr. Wilson’s has ever been widely considered offensive to the First Amendment.”

The Supreme Court reversed a unanimous decision from a three-judge panel of the U.S. Court of Appeals for the Fifth Circuit, in New Orleans, which had allowed the case to proceed, ruling that punishing an elected official for his speech can run afoul of the Constitution.

“The Supreme Court has long stressed the importance of allowing elected officials to speak on matters of public concern,” Judge W. Eugene Davis wrote for the panel, adding, “A reprimand against an elected official for speech addressing a matter of public concern is an actionable First Amendment claim.”

The full Fifth Circuit deadlocked on whether to rehear the case, by an 8-to-8 vote. Dissenting from the decision to deny further review, Judge Edith H. Jones said the panel’s First Amendment analysis was backward. The board’s censure was itself speech worthy of protection, she wrote, particularly in a polarized era.

“Given the increasing discord in society and governmental bodies, the attempts of each side in these disputes to get a leg up on the other, and the ready availability of weapons of mass communication with which each side can tar the other, the panel’s decision is the harbinger of future lawsuits,” Judge Jones wrote. “It weaponizes any gadfly in a legislative body.”

In a second dissent, Judge James C. Ho said that enduring condemnation is part of an elected official’s job description.

“Holding office in America is not for the faint of heart,” he wrote. “With leadership comes criticism — whether from citizens of public spirit or personal malice, colleagues with conflicting visions or competing ambitions, or all of the above.”