The only thing the all-male Sons of Confederate Veterans want is to honor their heroes—with historical reenactments, preservation of Confederate soldiers’ gravesites, genealogy services, and publications that highlight their heritage and sacrifice in their fight for freedom. And one way to honor their heroes is with specialty license plates depicting the Confederate flag, in a state with a long history of Confederate pride: Texas.

But Texas denied the group’s request at the behest of concerned citizens who found the flag design offensive. Now both camps will be facing off at the Supreme Court on Monday over whether the Constitution protects imagery and symbols on state-issued plates—even those the concerned citizenry may find unpleasant—as a form of free speech.

At first blush the question seems like a no-brainer, given the court’s strong stance against state efforts to suppress even the vilest forms of speech. But the law is not uniform across the country, and a good chunk of Americans—recall the debate surrounding the University of Oklahoma students expelled for racist chants—believe the government has leeway to sanction some expressive behavior. This case could prove a good teachable moment.

When the Texas Department of Motor Vehicles first considered the Sons of Confederate Veterans’ bid for the plates, the agency was clearly conflicted: It deadlocked in a four-to-four vote, with one member of the board mysteriously absent. The board then gave the public a chance to weigh in, and the comments were mostly negative. Taking the outcry into consideration, the board unanimously rejected the plates, explaining “that a significant portion of the public associate the confederate flag with organizations advocating expressions of hate directed toward people or groups that is demeaning to those people or groups.”

The board didn’t say what it meant by “demeaning,” but comments from the NAACP, church officials, and elected representatives brought to bear Texas’ own dark past of racism and oppression. Faced with the board’s rejection, Sons of Confederate Veterans sued Texas in federal court. After a setback early in the litigation, the group eventually won before the conservative U.S. Court of Appeals for the Fifth Circuit. In his decision, U.S. Circuit Judge Edward Prado wrote that Texas engaged in “impermissible viewpoint discrimination”—that is, it targeted the Veterans’ because of the symbol they asked the state to portray in the license plate, which the public found distasteful.

Pardo added this free-speech kicker: “We understand that some members of the public find the Confederate flag offensive. But that fact does not justify the board’s decision; this is exactly what the First Amendment was designed to protect against.”

Texas doesn’t see it that way. In its view, the Department of Motor Vehicles was entirely justified in denying the Veterans’ license-plate request under the notion of “government speech”—in other words, that the message on the plate is attributable to Texas, and that the First Amendment “allows a State to select the messages, symbols, and viewpoints that it is willing to publicly support.”

But Texas is mostly alone in its battle. In filings with the Supreme Court, a host of heavyweight organizations on the left and the right have thrown their support for the group’s free-speech claims, including the American Civil Liberties Union and the Becket Fund for Religious Liberty, the group that represented Hobby Lobby before the Supreme Court last year. Together, these unlikely allies hope to get across that a ruling for Texas might not only trump freedom of speech, but that it might do so at the expense of unpopular minorities or messages—be they religious minorities, pro-life advocates, or those without any beliefs.

The Supreme Court may be jumping into the fray because the law has been all over the place on license-plate controversies. Recently, North Carolina was chastised by a federal appeals court for approving a “Choose Life” license plate while denying a pro-choice plate. And a motorist who was denied a “COPSLIE” license plate convinced the New Hampshire Supreme Court that a state requirement of “good taste” in custom-made plates violated his First Amendment rights. But in Oklahoma, under a slightly different doctrine, a federal judge ruled that an image of a Native American holding a bow and arrow—standard on every plate—was not a religious message that compelled drivers to espouse a particular view.

Now, the court will specifically settle whether these plates represent government or private speech, and if the latter, whether rejecting an objectionable emblem tramples on speech rights. In doing so, the justices might well find favor with the Sons of Confederate Veterans, if only to expose a Texas-sized double standard: The state makes no secret of its Confederate past—by observing an official state holiday, by keeping statues of Confederate heroes on state campuses, even by selling souvenir Confederate currency in the Texas Capitol gift shop. Maybe approving a depiction of a Confederate flag on a license plate is not so much about the Constitution as about a state’s duplicitous stance on its history.