Texas motorists with an unbreakable attachment to the Lost Cause have many ways to advertise that allegiance while tooling down the road. They can decorate their vehicles with Confederate flag decals, bumper stickers or mud flaps. They can fly an actual Confederate flag from an attached pole. They can paint the flag on the roof, like the car in “The Dukes of Hazzard,” or elsewhere — doors, fenders, hood or tailgate.

But a lawyer for the Texas division of the Sons of Confederate Veterans (SCV) was at the U.S. Supreme Court last week arguing that the state has illegally abridged group members’ freedom to use their trucks and cars to communicate rebel pride. How? By refusing to issue a commemorative license plate with their name and design, which features that red flag with the blue X.

The state allows anyone to submit specialty plate designs, which are almost invariably approved by the Department of Motor Vehicles and offered to drivers willing to pay a premium. It rejected the SCV proposal, it says, because many Texans find the flag offensive and because the Constitution “allows a state to choose the messages and symbols that will appear on its specialty license plates.”

But a federal appeals court rejected that argument, concluding that “a reasonable observer would know that a specialty license plate is the speech of the individual driving the car,” not the state government. As “private speech,” it may not be censored by the DMV.

By that reasoning, the government may no more decline to offer a Confederate plate than it may ban Confederate bumper stickers.

But clearly there is a difference between pure private speech and what appears on a license plate. The plate is made by the state, sold by the state and required by the state as evidence of state authorization to operate the vehicle on public roads. It can be confiscated or destroyed by the decision of the state. It is, in short, an official totem.

When the state and the citizens it represents are effectively giving their blessing to something, they have the right to be selective.