The president had one job: to prove he was strong enough to take on his predecessor. Now Democrats must act, for America’s sake – and the world’s

What was the worst moment? Perhaps when one especially rambling sentence of Joe Biden’s ended in a mumbled, confused declaration that “We finally beat Medicare”, as if he were the enemy of the very public service Democrats cherish and defend. Maybe it was when the president was not talking, but the camera showed him staring vacantly into space, his mouth slack and open? Or was it when he was talking, and out came a thin, reedy whisper of a voice, one that could not command the viewer’s attention, even when the words themselves made good sense?

For anyone who cares about the future of the United States and therefore, thanks to that country’s unmatched power, the future of the world, it was agonising to watch. You found yourself glancing ever more frequently at the clock, desperate for it to end, if only on humanitarian grounds: it seemed cruel to put a man of visible frailty through such an ordeal.

Even Trump’s usual lies could not distract from the president’s decrepitude. But these debates don’t move the needle

Who could have foreseen that the scariest thing about the presidential debate on Thursday night wouldn’t be the lies, the bombast or the threats to democracy, but the spectacle of Trump’s slightly wolfish restraint. Heading into the encounter, Democrats felt the kind of anxiety more usually endured before watching a child perform, with that same crushing sense of raw emotions. That Trump barely mocked Biden, or went after his age or his son, seemed less rehearsed than a shrewd response to what all of us were seeing: a president so compromised that all Trump had to do was grin, lean back and let the optics work for him.

And still, despite the evidence, it feels wanton to say this. Biden, whose voice was hoarse from a cold, rushed his delivery, fought to find words and stumbled in a style not entirely new to him. The difference on Thursday night was one of degree. “Oh my God” was the general consensus, texted around the country, when the debate opened in Atlanta. While Trump’s remarks were predictably ludicrous, full of lies and inflated claims, nothing he said could distract from the image of Biden saying sensible things in a manner so crepuscular that the entire event jumped from politics to tragedy. It made me think of a line from Rilke: “It had almost hurt to see.”

In what felt like a Greek tragedy, Trump didn’t win the first presidential debate of 2024 – but Biden certainly lost it

That sickening thud you heard was jaws hitting the floor. That queasy sound you heard was hearts sinking into boots. That raspy noise you heard was a US president embodying what felt like the last gasp of the ailing republic.

Say it ain’t so, Joe.

Trump lied while Biden struggled to mount a coherent response. Our panelists weigh in on the first presidential debate

What a catastrophe. From the moment the debate started, Joe Biden was meandering, confused and charmless. It never improved. Donald Trump, however, was relatively restrained, at least for Trump. Of course, he resorted to lies, insults and exaggerations throughout the 90 minutes. By citing things called “Black jobs” and “Hispanic jobs” and by calling Biden a “bad Palestinian”, Trump managed to hit all his usual racist notes.

Moustafa Bayoumi is a Guardian US columnist

Jill Filipovic is the author of the The H-Spot: The Feminist Pursuit of Happiness

Lloyd Green is an attorney in New York and served in the US Department of Justice from 1990 to 1992

Arwa Mahdawi is a Guardian columnist and the author of Strong Female Lead

Osita Nwanevu is a Guardian US columnist

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The 90-minute debate is scheduled for 9pm ET inside a CNN studio in Atlanta, with Jake Tapper and Dana Bash as moderators

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