But the reality TV star wasn’t going to walk away—not from such high drama, not from such huge ratings. In an interview several years later, Trump told me that he viewed the debate as an experiment in “who likes pressure.” Voters wanted to see how a prospective president would handle being tested, being pushed. Trump responded to that pressure. With his back to the wall, facing scrutiny like no presidential hopeful in memory, Trump turned in his strongest stage performance of 2016. He was forceful but controlled. He was steady, unflappable, almost carefree. Even his most noxious lines, such as suggesting that Clinton belonged in jail, were delivered with a smooth cadence and a cool smirk, as if he knew a secret that others didn’t.

“That debate showed that I like pressure, because there was some pressure. What were the odds? Like 50-50, will he show up?” Trump told me. “That debate won me the election.”

I happen to agree with him. At a moment of genuine crisis, with his campaign on the brink of collapse just one month before the election, Trump projected a confidence that became contagious. The calls for his ouster ceased. The party got back to work boosting his candidacy. His poll numbers began to rebound. Trump had passed the pressure test. He had stopped the bleeding in ways that kept his base intact while demonstrating a resiliency, a certain defiance, that was appealing to some voters still on the fence.

I couldn’t stop thinking about that 2016 debate, and Trump’s subsequent analysis of it, during Tuesday night’s Cacophony in Cleveland.

The backdrop was awfully similar. With about a month until Election Day, trailing badly in the polls and urgently in need of resurgence, the burden of performance was on Trump. He came into Tuesday saddled not with a single calamity of “Access Hollywood” proportion, but with the collective weight of a pandemic that has killed some 205,000 citizens, an economic meltdown that has put millions out of work and a racial uproar that rips at the seams of American society. Because voting has started earlier than ever, diminishing the impact of later debates, there was zero time to spare. This was the 2020 version of Trump’s pressure test.

He failed miserably.

In the wake of Tuesday’s 90-minute barroom argument, many was the pundit who argued that we really shouldn’t be surprised. Trump is Trump. The hysterical norm-shattering guerilla we saw debating in Cleveland is the same hysterical norm-shattering guerilla we saw coming down the escalator in Manhattan. The manic president on stage was no different than the manic president on Twitter.

But this isn’t quite right. In reality, the candidate we saw Tuesday night—the worn, restless, curmudgeonly incumbent of 2020—bore little resemblance to the loose, rollicking, self-assured candidate of 2016. It might be hard to remember through the fog of these past four years, but the animating sentiment for Trump during his first run for the presidency wasn’t hatred or division. It was fun. He was having the time of his life. Nothing Trump had ever experienced had showered him with so much attention, so much adulation, so much controversy and coverage. He loved every moment of it. Even in the valleys of that campaign, such as Access Hollywood weekend, Trump found humor in razzing Rudy Giuliani or making jokes about Karen Pence. Even when he was lashing out against Clinton or the media or the Never Trump Republicans, he was enjoying himself.

The president wasn’t enjoying himself last night. There was no mischievous glint in his eye, no mirthful vibrancy in his demeanor. He looked exhausted. He sounded ornery. Gone was the swagger, the detached smirk, that reflected bottomless wells of confidence and conviction. Though described by Tucker Carlson in Fox News’ pregame show as an “instinctive predator,” Trump behaved like cornered prey—fearful, desperate, trapped by his own shortcomings and the circumstances that exposed them. He was a shell of his former dominant self.

It was shocking to witness. Whereas Trump four years ago was unemotional in his approach to Clinton, placid almost to the point of appearing sedated, he was twitchy and agitated from the opening moments of Tuesday’s debate. The president shouted and seethed and flailed his arms in fury, his face pulsating ever brighter hues of citrus. For all the talk of Trump throwing Biden off his game, it was Biden—and moderator Chris Wallace—who stirred such conniptions in the president that he was unable to meet the bare minimums. Despite being prepared for the obvious questions, Trump was so inflamed that he could not offer the vague outlines of a health care plan or denounce white supremacists with more than a single word—“Sure”—when gifted multiple opportunities to do so.

On the debate stage, Trump has long benefited from a commanding presence, an intimidating persona, that compensates for his lack of policy knowledge. This was the story of his success in the Republican primary season: He was never going to be the smartest kid in class, but he was always going to be the strongest. And yet, Trump didn’t come across as strong Tuesday night. He came across as spooked and insecure. The president who graduated from Wharton made fun of his opponent for getting bad grades. The president who is charged with guiding his country through a pandemic mocked the idea of wearing an oversized face mask. The president who promised to Make America Great Again depicted the U.S. (without evidence) as a failed state that can’t run a legitimate election.

Trump has lived his adult life by the gospel of Norman Vincent Peale and his mega-selling book, The Power of Positive Thinking. It preaches that there are no obstacles, only opportunities, and that overcoming them is a matter of belief and affirmative visualization. Watching the president on Tuesday night felt like watching someone losing his religion. Trump could not overpower Biden or Wallace any more than he could overpower Covid-19 or the cascading job losses or the turmoil engulfing American cities. For the first time in his presidency, Trump appeared to recognize that he had been overtaken by events. His warnings about the aftermath of the election doubled for his own political fate: “This is not going to end well.”

Facing pressure unlike any he has ever faced, the president of the United States came unglued. If his campaign for reelection fails, Trump cannot blame any one particular culprit. He can, however, look back on Tuesday’s debate as the bookend of his presidency, a moment in our history every bit as politically and psychologically significant as the one four years earlier.