They were the most ugly, unedifying, unpresidential ninety minutes of political campaigning that modern America has seen. With his campaign on the ropes going into last night’s second presidential debate against Hillary Clinton, Donald Trump faced two options: either to offer a contrite, unequivocal apology and display some trace of integrity, or to go out all guns blazing.

Senior Republicans, many of whom are themselves facing tough re-election battles, yearned for the former. But this is Donald Trump. He doesn’t do contrite. He doesn’t do humility. And he, quite frankly, has shown negligible interest in doing what is best for his party, let alone his country.

The tone was set from the beginning. The avoidance of a handshake was an ominous signal of the bitter acrimony that was to follow. Here are five takeaways from Trump’s gung-ho performance.

1. The denial
According to Trump, the Hollywood Access tape was “locker-room talk.” This was the classic non-apology: after expressing regret for what he said, he went on to dismiss people’s dismay as unfounded. His woeful equivocation has since prompted a series of sports figures to speak out against any conflation between ‘locker-room talk’ and making light of sexual assault.

2. The deflection
Before the debate he threatened to bring up decades-old accusations against Bill Clinton, and that’s just what he did. Trying to move attention away from his own behaviour, he claimed, “There’s never been anybody in the history of politics that has been so abusive to women.” Hillary Clinton didn’t engage. In one of her best lines of the night, she simply quoted Michelle Obama: “When they go low, we go high.”

3. The threat
Many viewers might have missed the significance of this moment when it happened, but Donald Trump essentially threatened his opponent in a fashion that would make the world’s most ruthless dictators proud. Vowing to appoint a special prosecutor on Hillary Clinton’s use of emails at the State Department, Trump issued her with this warning if he were to assume the presidency: “You’d be in jail.”

4. The chaos
Trump came to this debate better prepared than the first. He challenged Clinton on Obamacare, he challenged her on tackling economic inequality, and he challenged her on foreign policy. But while his attacks were stronger and more aggressive than in the first debate, his own policy prescriptions were as chaotic and incoherent as ever. He showed no understanding of how policies are made, within the confines of the US Constitution, and he openly rejected his own running mate’s position on Syria. On Mike Pence’s earlier vow to stand up to Russian aggression and promote humanitarian safe zones, Trump was dismissive: “He and I haven’t spoken, and I disagree.”

5. The stalking
The body language in this debate was fascinating. It was a town hall format, so the candidates were able to walk around and engage with the audience of undecided voters. Trump did something that no previous presidential candidate has done. He roamed around the stage when Hillary Clinton was talking, either pacing around out of personal discomfort or in an attempt to display intimidatory dominance against his opponent. If Trump sounds like a bully, he certainly looked like one too.

With such an ugly display, many will be left scratching their heads wondering why Hillary Clinton wasn’t able to take him down once and for all. She won, but not decisively. Three things prevented a knockout blow.

First, as we know, Hillary Clinton is not a perfect candidate. She still struggles to give a convincing answer to explain why she used a private server for her emails when she was Secretary of State, and she struggles to come across as trustworthy in the eyes of many Americans. Whatever her flaws she is, however, profoundly more qualified and fit to serve as president than Mr Trump ever will be.

Second, the town hall format itself made the exchange even more uncomfortable to watch. It’s not a format that is supposed to lend itself to bitter put-downs; instead, it’s supposed to allow each candidate to show how they can connect and engage with voters. Clinton tried to stay above the fray, but in doing so she risked coming across as defensive or evasive. She gave some great, much-needed answers that emphasized building unity across America, but she didn’t do much to address concerns over her trustworthiness.

Finally, the bar was so inexorably low for Trump going into last night’s debate that showing up at all could be spun as a bold comeback. He did what he does best at his rallies: he launched into visceral tirades that will reassure and energise many of his core supporters, but yet do nothing to broaden his appeal.

Trump’s defiant performance last night leaves the Republican Party facing its ultimate nightmare: their candidate is sufficiently healthy to carry on with his campaign, and sufficiently toxic to inflict lasting damage on their party and country. Today the most senior elected Republican, Paul Ryan, finally turned his back on Trump.

And it’s about time. Trump may not have lost last night’s debate decisively, but the American people already have lost enough during this presidential race. American democracy has already been demeaned beyond anyone’s wildest imagination this year; one man mustn’t be allowed to drag it even further into the gutter.

You can watch last night’s debate from St Louis in full by clicking this link.