Last week, activists protesting the Dakota Access pipeline burned a flag in Columbus Circle, one of only a few such publicized incidents in recent years.

First, there was incense lit and a prayer given by indigenous individuals. An activist called the flag “a symbol of colonialism.” Another explained solemnly why the flag would be burned.

Then it happened. An acrid scent spread, stronger than the incense.

Flag burnings like this don’t happen on every street corner but there is a history of them in New York, including one that resulted in a landmark Supreme Court case.

In 1966, decorated African-American WWII veteran Sidney Street was listening to the news in his Brooklyn apartment when he heard civil rights leader James Meredith had been shot and wounded. Street rummaged in his drawer to find what the court decision later called a “neatly folded, 48-star American flag which he formerly had displayed on national holidays.” Then he went outside and burned it.

A police officer later testified that he heard Street say, “If they let that happen to Meredith, we don’t need an American flag.”

Street was charged with malicious mischief; his case was appealed all the way to the Supreme Court, where the state law criminalizing his action was declared unconstitutional. Twenty years later, the court ruled flag burning is a constitutionally protected right.

And early Tuesday morning, from his high perch in Trump Tower, Donald Trump got himself into the same long-standing argument.

An argument with lots of history

“Nobody should be allowed to burn the American flag — if they do, there must be consequences — perhaps loss of citizenship or year in jail!” Trump tweeted from on high, perhaps in response to a Fox News report of a flag burning on Hampshire College’s campus that took place after the election.

Journalists and civil liberties advocates erupted at the tweet’s affront to the First Amendment.

The clumsy wording and wildly exaggerated punishment was noteworthy, but he was mostly advancing a debate that has been conducted along similar lines for decades.

Laws banning flag desecration and passed by forty-eight states were overturned by the Supreme Court in 1989. That ruling was reaffirmed in 1990, both by one-vote majorities. Since then, there have been multiple attempts to pass a constitutional amendment. In 2006, that motion failed to pass the Senate by a single vote.

But the argument for legal flag burning should be a simple one, when separated from politics and the queasiness that some might feel about this act toward a national symbol. As the Supreme Court has found, flag burning doesn’t do anything beyond make a political point.

It isn’t meant to directly harm another person, or even incite people to violence. It’s a protest, be it about governmental policies or cultural direction.

That’s easier to see in a case like Sidney Street’s in Brooklyn, where the flag burning is a direct response to an event. The act might feel broader when done by longtime provocateurs such as Gregory “Joey” Johnson, who identified as a communist and whose act led to the 1989 high court case. Johnson has continued burning flags, including at the Republican National Convention this year. Some may feel that flag burning is less defensible when done, as in the Hampshire College case, in a way that delegitimizes the new president.

But both are acts of peaceful protest, which Republicans and Democrats alike have defended as a fundamental core of American democracy.

It could be that this tweet is the last we hear from Trump on the issue, but it’s likely his tenure will see more burned flags. Partially, his tweet goaded opponents to do it, bait which will likely be taken particularly in centers of anti-Trump protest like New York.

Flag burnings are emotional

The city was home to many such acts, often clustered in another time of toil during the Civil Rights Movement and Vietnam War. In 1966, activists burned a flag during a skit at the Bridge Theater (a slightly more intense scene than what Vice President-elect Mike Pence encountered at “Hamilton”). A year later, another burning at an antiwar demonstration in Central Park. In 1970, another at a “flag art” exhibit.

In general, flag burnings are not very common, probably because of the depth of symbolic resonance — including the image of people burning American flags overseas — even for many who are eager to protest certain issues.

The wholesale symbol of the flag, for America writ large, good and bad, takes a large amount of anger and frustration to destroy. The act suggests: something is so wrong and unacceptable that the good is (at least temporarily) overshadowed.

Last week, the small crowd of NoDAPL protesters was mostly silent waiting for the flag to burn down. Some people looked away, others leaned in closer to take pictures. Some police officers looked on with expressionless faces.

It seemed a more extreme and somewhat disturbing act than the chants and marches of other protests. But the message was transmitted effectively, peacefully.

People went on with their lives.