WASHINGTON — The Trump reelection campaign told TV stations they could lose their operating licenses for airing an ad criticizing the president's actions in the coronavirus crisis — a challenge that may be more bluster than actual threat.

President Donald Trump's campaign, in a letter Wednesday, told stations in five battleground states to stop showing the ad from Priorities USA, a political action committee that supports Democratic candidate Joe Biden.

Failure to remove the ad "could put your station's license in jeopardy" before the Federal Communications Commission, the campaign said in the letter. "Your station has an obligation to cease and desist from airing it immediately to comply with FCC licensing requirements."

Trump has an antagonistic relation with much of the media, which he accuses of issuing what he calls "fake news." But the president has been accused by some news outlets of making misleading statements and telling lies, including regarding the coronavirus.

Trump has threatened retaliation before, including musing about challenging NBC's license in a 2017 tweet — even though licenses are generally held by stations, not networks.

Presidents appoint members to the FCC. The agency is led by Ajit Pai, a Republican designated as chairman by Trump. Another member of the FCC's Republican majority awaits Senate confirmation for a third term at the agency.

The FCC doesn't appear to have grounds to act against the stations for airing contentious ads, Jack Goodman, a Washington broadcast attorney, said in an interview. The ad "is core political speech" protected by First Amendment guarantees of free speech, Goodman said.

"This is the sort of letter that stations get in political years, day in and day out," Goodman said. "It's intended to intimidate."

A license revocation would not be likely under any scenario, said Andrew Jay Schwartzman, senior counselor at the Benton Institute for Broadband & Society. Eventually a license renewal could be challenged before the FCC, but "such a petition would get nowhere."

The Trump campaign said it sent the letter to stations it did not identify in Florida, Michigan, Minnesota, Pennsylvania and Wisconsin.

The ad from Priorities USA shows U.S. coronavirus cases growing from Jan. 20 to March 22 while featuring audio of Trump downplaying the threat during that time. "The coronavirus," Trump says at the beginning, before a second clip plays, "this is their new hoax."

The Trump campaign says the president was describing Democrats' efforts to politicize the coronavirus, not calling the virus itself a hoax.

On Thursday the Trump campaign declined to comment, and the FCC didn't immediately reply to an email seeking comment.

Dennis Wharton, a spokesman for the National Association of Broadcasters, also declined to comment.

Priorities USA responded to the Trump team's "intimidation effort" by announcing Thursday that it would keep running the ad and also begin airing it in Arizona, where the group said it plans to spend $600,000 over the next few weeks.

"Trump's super-PAC and now Trump's campaign are resorting to desperate threats to keep Americans from hearing the truth," said Patrick McHugh, the executive director of Priorities. "Priorities USA will continue ensuring voters hear the truth."

A pro-Trump super-PAC, America First Action, said it sent a letter complaining about the ads to broadcasting companies including Tegna Inc., Sinclair Broadcast Group Inc. and Hearst Television Inc.

Gene Policinski, senior fellow for the First Amendment at the Freedom Forum Institute, said previous administrations may have spoken privately about challenging licenses, but Trump was unusual for saying it out loud.

"This goes back to Nixon in the '60s, talking about revoking stations critical to his administration," Policinski said.

In 1972, President Richard Nixon urged his lieutenants to interfere with the renewal of The Washington Post's licenses for Florida TV stations. The company's stock price took a hit, and defending the licenses cost the Post more than $1 million in legal fees over 2 { years, Publisher Katharine Graham wrote in her memoir in 1997.

"Of all the threats to the company during Watergate — the attempts to undermine our credibility, the petty slights, and the favoring of the competition — the most effective were the challenges to the licenses of our two Florida television stations," Graham wrote.