Donald Trump during yesterday’s press conference. Photo: Mario Tama/Getty Images

Donald Trump’s disorienting, surreal press conference contained one moment of pristine clarity, when the president predicted, “Tomorrow, the headlines are going to be, ‘Donald Trump rants and raves.’” This prediction, while quite correct, raises the question of why Trump thought it was a good idea to hold a media event whose principal effect would be to produce headlines depicting him as rambling and unhinged. Reports from the administration have supplied the answer, which is quite simple: His boasts spring from a place of utter, self-delusional conviction.

Trump, reports Mike Allen, “truly believes this had been the best start to a presidency in history, and no one around would ever disagree to his face.” The New York Times has the same account, with more detail. “For days, a frustrated and simmering president fumed inside the West Wing residence about what aides said he saw as his staff’s inadequate defense and the ineffectiveness of his own tweets,” it reports. “Over the objections of some top advisers who wanted to steer him away from confrontation, Mr. Trump demanded to face the media, determined to reject the narrative that his administration is sinking into chaos, scandal and incompetence.”

Almost all of Trump’s planned remarks expressed some version of this single belief. “I don’t think there’s ever been a president elected who in this short period of time has done what we’ve done,” he insisted. (This is not even close to true: Barack Obama’s first month had vastly larger and more consequential policy changes.) Trump boasted, again, of “the biggest Electoral College win since Ronald Reagan.” (In fact, it was merely the biggest Electoral College win since … Obama in 2012.) He twice cited a Rasmussen poll, which “just has me through the roof” — Rasmussen being a conservative messaging firm that is not considered reliable by real pollsters. He glommed onto other factoids that had crossed into his view and confirmed his self-confidence. The stock market is up! He’s expecting a big crowd for his weekend rally!

Trump is not a data person. He is an anecdote person. And these anecdotes all support his sense of dizzying triumph. He had assembled “one of the great cabinets ever assembled in American history. You look at Rex Tillerson. He’s out there negotiating right now.” One can easily see how, to a mind like Trump’s, the report that the secretary of State he appointed is already out in the world negotiating would imply progress and fill him with satisfaction. It may be normal for a secretary of State to negotiate with other leaders, but it is not normal to Trump. It is new and exciting. It is the sort of development that would allow him to overlook details like the man he asked to serve as national security adviser — after he had to fire his last national security adviser for lying to his vice-president and the FBI — had turned him down in humiliating and public fashion. Or that six of his staffers had to be dismissed for failing background checks, or that Tillerson is conducting his negotiations from a sanitarium because nobody booked him a room in time with the other world leaders.

Trump, as many have noted, is the world’s highest-profile case of the Dunning-Kruger effect, which is the phenomenon by which incompetent people are unable to gauge their own competence. Of course, Trump is not bereft of talent. He mastered the technique of using the media to raise his profile, flooding the news with arresting quotes and tidbits and scandal, turning the ordinary heir to a real-estate portfolio into America’s most famous rich person — a branding triumph that he leveraged into a lucrative licensing operation, some outright swindles, and, most crucially, a television show in which he played a brilliant executive.

All the evidence suggests Trump truly believes he is the character he plays on television. And now that he is surrounded by courtiers and the trappings of power, and constantly flattered by powerful people who are secretly terrified of his incompetence, he is convinced of it more deeply than he ever has been before.

You can watch the wildest moments from the press conference here: