I was at the Trump-Biden presidential debate and it became very clear, very quick what had gone wrong

Behind the scenes at the first debate between Joe Biden and Donald Trump, the buzzy atmosphere of the spin room descended into horror-struck silence within a first few minutes of the president opening his mouth. While Trump told bombastic lies in front of us, Biden struggled to recall what were obviously canned responses.

At one point, a former prominent TV commentator got up from their seat and start pacing back and forth, worriedly. Biden aides and surrogates, who had been in constant communication with each of us throughout the day, fell silent, one by one.

When the cameras stopped rolling and the debate was over, a whole team of Trump surrogates flooded onto the spin room floor. That included multiple Republicans – Ben Carson and Lindsey Graham among them – who have been vying for the ex-president’s favor as he seeks a new veep pick.

All of those Republican operators and Maga staff members were eager to tell us reporters how Biden’s performance had telegraphed weakness on the world stage. They confidently declared that Trump had won.

By contrast, the Biden surrogates were nowhere to be found.

While some of the assembled press were interested in what the Republicans had to say, the vast majority were looking for Biden’s backers to defend his performance.

Finally, they came out as a group, grim-faced, to face a wave of reporters, producers and videographers at the far end of the spin room. Their sudden appearance led to a comically packed scrum, with your correspondent being crushed between an NBC reporter, a Biden spokesperson and the sitting governor of California, Gavin Newsom – who everyone had already started whispering about replacing the president.

I held up a recorder to capture their words as they recited their talking points, struggling to breathe.

Biden campaign communications director Michael Tyler told us that viewers saw in the president’s performance “a very clear contrast” with Trump and “a very clear choice in this election”. He also said Trump had “took the stage and lied the entire night, grew increasingly unhinged throughout the night and reminded the American people by the end of the debate exactly why they fired him in the first place four years ago.”

But we all knew the real truth. And most of us also knew why.

Earlier in the week, I spoke to multiple Biden campaign strategists and former Democratic operatives about how the president was preparing for the debate at Camp David. All of them described a punishing and rigorous process during which Biden would practise hitting back at various criticisms and insults expected from Trump on the night.

Their strategy had one major flaw: it relied on memory – not the president’s strong point, at 81 years of age – and on the delivery of facts. Facts are all very well and good during a political campaign and, of course, are paramount for policy. But debates are about who you are. Trump knows that very well.

Indeed, when my colleague Eric Garcia asked Democratic representatives in Congress what they thought Biden should remember on the stage ahead of Thursday night, they kept repeating one line: “Be himself.”

Yet Biden had very little space to be himself among those pre-prepared lines. He was at his best when he was being extemporaneous during the debate (for there were good moments for the president, even if they were few and far between) rather than recalling minutiae. Where he could’ve projected personality, he instead exposed his own concerning downsides.

Trump, in contrast, relied on being himself, and came out looking just fine. The supposed facts he often pulls out the air may be questionable, but that’s not what matters when the lights are on and the cameras are rolling.

A close confidante of the president who assisted with his debate prep for the past week replied to a query from The Independent about Biden’s early stumbles by pointing out that he was starting to hit back on Trump harder than he had in the past. And it’s true that Biden did try that. Fifteen minutes in, he finally began landing blows, at one point hitting Trump as a “sucker” and “loser” after he claimed to have done more to help injured veterans than Biden, who earlier this year signed the largest veterans aid bill to pass Congress in decades. He also took aim at Trump’s status as a convicted felon, his anti-Nato isolationism, and the ex-president’s frequent and blatant lies about the legal cases he faces in three other state and federal courts.

But it just wasn’t enough.

Gavin Newsom, who for months has been alleged to be positioning himself as waiting in the wings when Biden withdraws, echoed other surrogates’ talking points to reporters right after the debate wrapped up.

“I’m a little old-fashioned. I care about policy. I care about facts,” he said.

As campaign aides shouted down reporters who attempted to ask him if he’d step in as Biden’s replacement if called on, Newsom said he was “very proud” of the president’s performance.

He also vehemently denied that he would even consider stepping in were Biden to be removed or step down.

“I would never turn my back on President Biden,” he said.

Whether he might help him out by taking over if called upon, however, might be another thing entirely.