A SUBURBAN police station in Maryland displayed a thin-blue-line flag — an American flag doctored with a horizontal blue bar substituted for a red one — and probably thought it represented nothing more than a tribute to law enforcement officers. If only it were that simple.

Now the Germantown station, in Montgomery County, finds it has triggered a fight over dueling interpretations of what and whom the flag affirms or offends. For in addition to symbolizing respect for the police, the flag has been adopted by some, including white supremacists, as a racially loaded repudiation of Black Lives Matter.

Mindful of that, the county executive, Marc Elrich, ordered that the flag not be publicly displayed at the station. That was the right call, and Gov. Larry Hogan (R) made an ill-considered move by entering the fray in the flag’s favor, tweeting photographs of himself before similar flags and thereby inflaming the culture wars.

It would be nice to think of the flag as a harmless hat tip to the Montgomery County police, a generally excellent and well-regarded department. It may well have been intended that way by the local man and his son who gave it to the police as a gift. Regrettably, the flag has been appropriated by exponents of hatred. To pretend otherwise is to enable them while turning a blind eye.

Police officers play a unique role in any community, deserving of respect and charged with showing the same to others. Their effectiveness depends on how they conduct themselves — the degree to which they are regarded as evenhanded arbiters, beyond reproach.

That’s a tall order. Smart police departments err on the side of caution. Mindful of that, Mr. Elrich, a Democrat who is the county’s top elected official, had the flag removed in the name of “improving police relations with the community.”

The union representing the police expressed fury, and Mr. Hogan chimed in that removing the flag was “outrageous and unconscionable.” Perhaps the governor was unaware that some of the white supremacists who wreaked havoc in Charlottesville in 2017, spouting racist bile and chanting “Jews will not replace us,” carried the thin-blue-line flag. Mr. Hogan, a Republican in a mostly Democratic state, has tended to sidestep the tribal conflicts that are tearing the country apart.

It’s not easy to know at what point a once-neutral symbol has been irredeemably tainted by appropriators. Neo-Nazis calling themselves the Detroit Right Wings hijacked the logo of the National Hockey League’s Detroit Red Wings and edited in the SS “bolt” symbol; the team renounced the alteration and kept the logo. But the thin-blue-line flag is much less recognized and therefore more susceptible to symbolic capture.

As it happens, it’s against federal law to remake the American flag with “any mark, insignia, letter, word, figure, design, picture, or drawing of any nature.” Displaying a flag that is not only illegal but also a lightning rod for controversy is not a good look for a police station.

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