The chairman of the Federal Communications Commission has waded into the politicized debate over NPR and PBS, ordering up an investigation that he said could be relevant in lawmakers’ decision about whether to continue funding the public news organizations.
Brendan Carr, the chairman, said in a letter to NPR and PBS on Wednesday that the inquiry would focus on whether the news organizations’ member stations violated government rules by recognizing financial sponsors on the air.
Mr. Carr said that NPR and PBS stations operate as noncommercial broadcast organizations, but that they may be airing “announcements that cross the line into prohibited commercial advertisements.”
“To the extent that these taxpayer dollars are being used to support a for-profit endeavor or an entity that is airing commercial advertisements,” Mr. Carr wrote, “then that would further undermine any case for continuing to fund NPR and PBS with taxpayer dollars.”
The letter is the latest action from President Trump’s allies to target NPR and PBS stations and the Corporation for Public Broadcasting, a taxpayer-funded organization that backs them. Executives at NPR and PBS stations have been bracing for a potential battle over government funding, gaming out financial worst-case scenarios.
Mr. Carr, who was appointed by Mr. Trump, said he did not see a reason for lawmakers to continue funding the organizations. He said that he planned to notify members of Congress about his investigation.
Katherine Maher, the chief executive of NPR, said in a statement that the organization’s practice of using sponsorships, also known as underwriting, “complies with federal regulations.”
“We are confident any review of our programming and underwriting practices will confirm NPR’s adherence to these rules,” Ms. Maher said. “We have worked for decades with the F.C.C. in support of noncommercial educational broadcasters who provide essential information, educational programming, and emergency alerts to local communities across the United States.”
PBS said in a statement that it was proud of “noncommercial educational programming,” and worked “diligently to comply with the F.C.C.’s underwriting regulations.”
Two F.C.C. commissioners released statements taking issue with Mr. Carr’s investigation. Anna Gomez, a Democrat, said that the investigation appeared to be an attempt to “weaponize the power of the F.C.C.” Geoffrey Starks, also a Democrat, said that Mr. Carr’s statement gave him “serious concern.”
NPR and PBS have for decades aired sponsorships under rules set forth by the government. While public broadcasters are restricted by law from accepting traditional commercials, the F.C.C. has become more permissive over the years about what public stations are allowed to air. The F.C.C.’s evolving stance on the issue has gradually allowed public radio stations to become less dependent on government funding.
Eric Nuzum, a former NPR executive and co-founder of the audio consulting and production company Magnificent Noise, said that sponsorships and underwriting differ sharply from advertising on commercial TV and radio in several respects.
“The difference is, in a commercial, the sponsor can say anything they want — it’s their time,” Mr. Nuzum said. “In an underwriting situation, the station provides an acknowledgment of who’s providing the funding, along with basic information about the underwriter.”
Bills are working their way through Congress that would defund public media, including the No Propaganda Act, introduced by Senator John Kennedy of Louisiana and Representative Scott Perry of Pennsylvania, and the Defund NPR Act, introduced by Representative Jim Banks of Indiana.
Earlier this week, NPR executives told staff members that a memo issued by Mr. Trump’s administration imperiled two grant programs benefiting local stations, citing guidance from the Corporation for Public Broadcasting. Mr. Trump’s administration rescinded that memo after it was blocked by a judge.
Seth Stern, the director of advocacy at Freedom of the Press Foundation, said he believed Mr. Carr seemed to be setting up a legal pretext for interfering with public media.
“The end of Mr. Carr’s letter tellingly goes far beyond underwriting and talks about his thoughts on whether public media should be funded at all and notes that this underwriting issue might be relevant to a broader legislative debate,” Mr. Stern said. “That was troubling to read.”