Trump, now against kneeling during anthem, once seemed to say flag burning was free speech

— -- President Donald Trump's assertion that NFL players who kneel in protest during the national anthem should be fired for "disrespecting" their country appears consistent with his stance shortly after his election that flag burning should be illegal.

But Trump's emphasis on the need to show respect to U.S. symbols appears to reflect a change from before he ran for president when he seemed to view flag burning as free expression.

In an interview with David Letterman on Jan. 8, 2015, just months before Trump launched his presidential campaign, he seemed to agree with Letterman "100 percent" that flag burning is a form of expression.

As first reported by The Washington Post, Trump and Letterman were discussing the terrorist attack on the French satirical newspaper Charlie Hebdo. The conversation turned to freedom of speech and flag burning as an example of it.

“Here’s the example I’m always proud of as an American,” Letterman countered. “People, to demonstrate, they think, ‘We’re really going to stick it the United States. We’re going to set fire to the flag.’”

“Yeah, right,” Trump responded.

“And people get — ‘Oh, my God!’ ” Letterman said. “Well, no. If that’s how you feel, go ahead and burn the flag. Because this country is far greater than that symbol, and that symbol is standing for freedom of expression.”

“Sure. You’re 100 percent right,” Trump said, adding, “I understand where you’re coming from. It’s terrific.”

But by a few weeks after his election, Trump appeared to have a different view on flag burning. In a tweet Nov. 30, 2016, he suggested that those who burn the American flag should be jailed or have their citizenship revoked. His transition team did not respond to ABC News' request for comment at the time.

His views now on NFL players and the national anthem appear to be in the same vein.

On Friday, Trump at a rally in Huntsville, Alabama, said NFL owners should fire players who kneel in protest during the national anthem.

"You know, some owner ... is going to say, 'That guy who disrespects our flag, he’s fired,'" the president said to applause and cheers.

According to court rulings, burning the American flag is a protected form of expression under the First Amendment. Justice Antonin Scalia, whom Trump has repeatedly praised, acknowledged flag burning as a right though he hated the idea of it, he told CNN in 2012.

"Yes, if I were king, I — 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. I mean, that was the main kind of speech that tyrants would seek to suppress. Burning the flag is a form of expression. Speech doesn't just mean written words or oral words ... Burning a flag is a symbol that expresses an idea," Scalia said at the time.

ABC News' Chris Donovan contributed to this report.