On Tuesday, president-elect Donald Trump took to Twitter to threaten to jail anyone who burns the American flag.

“Nobody should be allowed to burn the American flag — if they do, there must be consequences,” Trump tweeted. “Perhaps loss of citizenship or year in jail!”

It’s not clear what motivated the tweet, though flag burning has been ruled to be constitutional and protected under the First Amendment.

What’s more, the late Supreme Court Justice Antonin Scalia spoke on flag-burning, saying in 2012, “If I were king, I would not allow people to go about burning the American flag. However, we have a First Amendment, which says that the right of free speech shall not be abridged. And it is addressed, in particular, to speech critical of the government.”

He added that it would be dictatorial to ban any form of free speech: “I mean, that was the main kind of speech that tyrants would seek to suppress.”

Scalia’s death has left a vacancy on the Supreme Court that Trump will be expected to fill.