On Twitter, President Trump deployed the phrase “fake news” 273 times this year — 50 percent more often than he did in 2018. He demanded “retribution” over a “Saturday Night Live” sketch, declared that Washington Post reporters “shouldn’t even be allowed on the grounds of the White House,” and accused The New York Times of “Treason.”

Four American journalists were barred from covering the president’s dinner with the North Korean leader, Kim Jong-un. The administration argued in court that it had the right to ban a reporter from the White House. The daily White House briefing ceased to exist. And a new press secretary rarely spoke in public outside Fox News.

Mr. Trump’s vilification of the news media is a hallmark of his tenure and a jagged break from the norms of his predecessors: Once a global champion of the free press, the presidency has become an inspiration to autocrats and dictators who ape Mr. Trump’s cry of “fake news.”

For those who wondered if Mr. Trump might heed the concerns of historians and First Amendment advocates — who say his actions have eroded public trust in journalism, and perhaps the very concept of empirical facts — 2019 provided a grim answer.