Jennifer Palmieri, the communications director for Hillary Clinton’s 2016 presidential campaign, said she learned the hard way about fighting Mr. Trump’s disinformation. “It is extraordinarily hard to combat,” she said, adding that it became clear to her that he was willing to say and do anything when in 2015 he mocked Senator John McCain’s status as a war hero and paid no price.
Asked about Mr. Trump’s behavior over the decades, Judd Deere, a White House spokesman, did not respond directly. “The American people know they never have to wonder what the president is thinking or how he feels about a particular topic, which is one of the many reasons why they chose to elect him over the same old recycled politicians who just use the poll-tested talking points,” Mr. Deere said.
Mr. Trump’s approach has been remarkably consistent, and often successful, as he has lied and spread falsehoods on matters big and small over the years. And he has found his biggest audience for it in the past five years.
“Americans have had a paranoid streak throughout their history, which this guy understands better than anybody,” said Hank Sheinkopf, a Democratic political strategist who watched Mr. Trump over decades in New York City. “If Joe McCarthy was alive, he’d say, ‘Well done.’”
When Mr. Trump was trying to get a tax abatement in 1982 to build Trump Tower on Fifth Avenue, the New York City housing commissioner at the time, Anthony B. Gliedman, received a mysterious call from someone who harassed him because the abatement had been denied.
The next day, Mr. Trump called the F.B.I. and said that he, too, had received a call from someone claiming to have read in the newspapers about the tax abatement being held up, according to F.B.I. records obtained by BuzzFeed. Mr. Trump claimed in the call, according to the F.B.I. records, that the caller mentioned someone else who had been “shafted” by Mr. Gliedman and that the caller planned to retaliate.
Mr. Trump, who has alternately derided and worked with the F.B.I. since his earliest days as a developer in New York — where organized crime had deep ties to the construction industries — told the F.B.I. officials he was reaching out to them in fear for Mr. Gliedman’s safety.