IF THERE were a First Amendment Hall of Shame, one notorious inductee would be the West Virginia Board of Education, which expelled the daughters of Walter Barnette from their public school for refusing, on religious grounds, to salute the flag and recite the Pledge of Allegiance. In an impassioned 1943 ruling, the Supreme Court reproached the state for suppressing the girls’ freedom of expression. “If there is any fixed star in our constitutional constellation,” the court declared, “it is that no official, high or petty, can prescribe what shall be orthodox in politics, nationalism, religion, or other matters of opinion or force citizens to confess by word or act their faith therein.”

Another exhibit in a gallery of First Amendment villains would feature the school officials in Des Moines who in 1965 suspended 13-year-old Mary Beth Tinker and other students for wearing black armbands to protest the Vietnam War. Once again the Supreme Court sharply admonished school officials for their censorship. Students do not “shed their constitutional rights to freedom of speech or expression at the schoolhouse gate,” the high court proclaimed, and “they may not be confined to the expression of those sentiments that are officially approved.”

Now the Supreme Court is being asked to take up the case of Liam Morrison, a student at the Nichols Middle School in Middleborough who was barred from class last year for wearing a T-shirt with the message “There Are Only Two Genders.” If the justices agree to hear the case, the Middleborough School Committee and the principal of Nichols can expect to find themselves added to the First Amendment rogues’ gallery for having suppressed Morrison’s speech instead of protecting it.

The school claimed the boy’s “only two genders” shirt violated the school’s dress code, which forbids students to wear anything that “target[s] groups based on race, ethnicity, gender, sexual orientation, gender identity, religious affiliation, or any other classification.” Morrison’s parents sued the town for violating their son’s constitutional rights, but the US district court in Boston dismissed the complaint. The First Circuit Court of Appeals upheld that decision, ruling in June that officials were entitled to suppress Morrison’s opinion on the grounds that “the shirt demeaned the gender identities of other students” and would likely have a “disruptive impact on the learning environment.”

Yet even the First Circuit acknowledged that Morrison, a seventh-grader at the time, expressed himself “passively, silently, and without mentioning any specific students.” The words on his T-shirt criticized no one, targeted no one, and certainly “demeaned” no one. What it did do was challenge a contrary viewpoint — one that Middleborough officials openly endorse.

At Nichols, students are not only permitted but encouraged to embrace the belief that there are more than two genders. Middleborough teaches “that sex and gender have no biological foundation, are limitless, and are based on personal identity,” court filings showed. Pride flags are displayed in Morrison’s school, as are posters with messages like “Rise Up to Protect Trans and GNC [gender non-conforming] Students” and “Proud friend/ally of LGBTQ+.” During June, Nichols students are exhorted to “wear your Pride gear to celebrate Pride Month.”

What this case is about, in other words, is whether a public school can come down firmly on one side of a hotly debated topic while silencing a student who expresses a contrary view. Under the First Amendment, the answer is no. Just as the government had no right to force dissenting West Virginia schoolgirls to recite the Pledge of Allegiance, just as Des Moines had no right to retaliate against Mary Beth Tinker for opposing the Vietnam War, so too Middleborough had no right to prohibit 12-year-old Liam Morrison from quietly and politely disagreeing with his school’s position on gender.

The Supreme Court is being asked to review this case in part because the First Circuit’s decision to uphold Middleborough’s censorship is in conflict with most of the other circuits. The attorneys general of 18 states make that point in a friend-of-the-court brief urging the justices to take up the case.

But their argument goes further. They emphasize that a core function of public schools is to “prepare pupils for citizenship in the Republic” by inculcating values critical in a democracy — including “the ability to respectfully engage in public debate about the big questions facing society.” By letting Middleborough discriminate against one student’s viewpoint, the AGs write, the First Circuit “undercuts one of the most important purposes of public education: forming civic virtues by pursuing truth — even when uncomfortable.”

The First Amendment does not allow public schools to prohibit courteous dissent. It does not authorize the government to stifle opinions because some find them unwelcome. Officials may believe they have good reason “to coerce uniformity of sentiment,” as the Supreme Court has written, but good intentions do not override the Constitution. Since the court of appeals failed to say so, the nation’s highest court must.