A few days ago, as Puerto Rico and other American territories were reeling from the aftermath of Hurricane Maria, President Donald J. Trump had other things on his mind – primarily professional football players who chose to “take a knee” during the playing of the National Anthem.

As usual, Trump kicked things off with an obligatory string of tweets. He then ramped up the rhetoric in other forums.  

“Wouldn’t you love to see one of these NFL owners, when somebody disrespects our flag, to say, ‘Get that son of a b*tch off the field right now, out, he’s fired? He’s fired,’” Trump said at a Sept. 23 rally, referencing pro football players who have been kneeling during the anthem to protest racial injustice. “You know, some owner is going to do that. He’s going to say, ‘That guy that disrespects our flag, he’s fired.’ And that owner, they don’t know it [but] they’ll be the most popular person in this country.”

Trump’s rhetoric stands in contrast with the words of the U.S. Constitution. Under the First Amendment, people can’t be compelled to stand for patriotic or religious ceremonies if they don’t want to. That includes the National Anthem. Obviously, the NFL is not bound by the First Amendment, but, as President, it is disappointing that Trump does not appear to value freedom of speech.

Trump also fails to grasp what’s going on here: This started as a protest over racial injustice, not the anthem itself. In that sense, the protests were not unpatriotic – but even if they were, it would not matter. It’s a violation of basic rights to compel someone to participate in a patriotic ritual.

Nevertheless, some of Trump’s most prominent supporters, including former White House chief strategist Steve Bannon, have praised his comments.  

“If people in this country take a knee and the National Football League players want to take a knee, they should take a knee at night, every night, and thank God in heaven Donald J. Trump is president of the United States,” Bannon told Fox News in a Sept. 25 interview. “He has saved this country so much grief. He has done such a tremendous job with virtually no help.”

Trump, Bannon and many of their backers are abysmally ignorant of the history of this issue. Americans have the right to decide if they will take part in patriotic rituals thanks to a 1943 church-state case called West Virginia State Board of Education v. Barnette

Players have the right to protest during the National Anthem.

The Barnette case occurred in the public school context and concerned the Pledge of Allegiance, not the National Anthem – but the general principles laid down in the decision are clearly applicable here.

Many states used to have laws requiring public school students to salute the flag and recite the Pledge of Allegiance every morning. Jehovah’s Witnesses argued that their only allegiance was to God and instructed their children not to take part. Witnesses’ children were expelled from some public schools, and the matter entered the courts.

In 1940, the Supreme Court actually upheld mandatory participation in the flag ritual in public schools in a case from Pennsylvania titled Minersville School District v. Gobitis. But just three years later, the high court took up the matter again and ruled the other way in Barnette.

The ruling contains this eloquent and often-quoted passage by Justice Robert H. Jackson: “If there is any fixed star in our constitutional constellation, 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.”

Why did the court reverse itself so quickly? In part because many Jehovah’s Witnesses were attacked in the interim. (There had also been some changes among personnel on the court.)

Although NFL players are not objecting to the anthem for religious reasons as students in the Gobitis and Barnette cases did, Barnette laid down a powerful rule: If participation in a patriotic ritual clashes with the right of conscience, the latter takes precedence.  

So, as week four of the NFL season kicks off tonight, players can, when the National Anthem is played, take a knee, lock arms or stand. It’s their constitutional right to choose as they please.

Thanks to the Barnette church-state case, we all have that right – and we should be thankful for it.