The owners of the 32 National Football League teams sent a wrongheaded and, frankly, un-American message to their players Wednesday: Expressing your opinion during the national anthem is no longer permitted.

“A club will be fined by the League if its personnel are on the field and do not stand and show respect for the flag and the Anthem,” the league announced. “Each club may develop its own work rules, consistent with the above principles, regarding its personnel who do not stand and show respect for the flag and the Anthem.”

This is the NFL’s solution to the culture-war battle that began with a small and quiet act of defiance two seasons ago, when former San Francisco 49ers quarterback Colin Kaepernick sat on the bench instead of standing with his teammates while the anthem was played. Kaepernick later explained that he was protesting police brutality and “a country that oppresses people of color.”

The protests continued last season without Kaepernick, a gifted athlete who somehow could not get re-signed in a league that preferred such lesser lights as Chad Henne, Blaine Gabbert, Paxton Lynch and Chase Daniel. And then suddenly they escalated, in no small part because President Donald Trump turned his contempt for the protests into an applause line. “Two dozen NFL players continue to kneel during the national anthem, showing total disrespect to our Flag & Country. No leadership in NFL!” he tweeted in October.

To their credit, players rallied around their protesting teammates, and team owners largely stuck by their employees. That changed Wednesday, when the owners caved to Trump’s demand that players be brought to heel. At the moment, the league is threatening to penalize teams whose players don’t comply; it remains to be seen whether the teams will pass those fines onto the players themselves.

The owners may well have the authority to do that, depending on whether such disciplinary issues have to be negotiated with the players’ union. (The union is looking into that issue.) Private businesses are free to muzzle their workers as a condition of employment; the First Amendment’s restraints apply only to the government.

Yet isn’t it more than a little un-American to demand that citizens salute the flag and “show respect” for the national anthem? And isn’t it quintessentially American to protest, as Kaepernick did? Even if the First Amendment doesn’t apply to private businesses, surely the NFL owners should feel a little chagrined knowing that more than 70 years ago, the U.S. Supreme Court ruled that children in public schools can’t — and shouldn’t — be forced to salute the flag or pledge allegiance to it.

There is one apparent escape valve in the new NFL policy: The league will no longer require players to be on the field for the playing of “The Star-Spangled Banner.” As far as the league is concerned, if they’d rather not stand respectfully for the anthem on the field, players can stay in the locker room and assume whatever posture they please. But individual teams may still try to require their players to be on the field. And even if they don’t, it’s just a matter of time before players who don’t want to stand for the anthem come under fire for staying in the locker room.