WHEN PRESIDENT TRUMP called the U.S. news media “the enemy of the American People” and brandished the moniker “fake news” at reports he didn’t like, tyrants everywhere perked up. They heard the president say exactly what they have been saying about nettlesome journalists who expose human rights abuses, corruption and rigged elections. Mr. Trump’s remarks have a ripple effect overseas, signaling that the United States will no longer champion freedom of the press and expression. This will inevitably lead to more repression.

Cambodia, which last year sentenced a man to 18 months in prison for a Facebook post, was one of the first to seize upon Mr. Trump’s approach. A government spokesman, noting how the White House had barred several U.S. outlets from a briefing, warned Radio Free Asia and Voice of America about their news coverage, which is quite straightforward and therefore threatening to the government of Prime Minister Hun Sen. The spokesman declared, “Freedom of expression is subject to law and must respect the state’s power.”

Respect of state power and the ruling Communist Party is also what China demands in no uncertain terms from its news media, insisting they “have the party as their family name.” China’s propagandists have started to mimic Mr. Trump’s methods in news articles. The party’s leading newspaper, People’s Daily, denounced Western news coverage of a Chinese lawyer and human rights advocate who said he had been tortured by splashing a photograph with the words “FAKE NEWS.” The paper said it was “fabricated to tarnish China’s image.”

In Russia, where press freedom has been corralled into a small space under President Vladimir Putin and the dark arts of propaganda and disinformation are well practiced, the Foreign Ministry has set up a new section of its website for “fake news,” with a big red stamp of “FAKE” for reports that it does not like. Among those so branded was a New York Times article describing the new practice.

Mr. Trump has a personally contradictory relationship with the news media. He has long hungered for favorable coverage. But he appears to see the news media in strictly promotional terms, not as a mechanism of democracy to probe and criticize.

His behavior has global consequences. The press would not be free in Cambodia, China or Russia if a different U.S. president had been elected. But the United States has a long tradition of speaking out against crackdowns on the news media, and sometimes those interventions make a difference. Secretary of State Rex Tillerson says that “American foreign policy must promote our core values of freedom, democracy and stability.” Does the president agree?