It started off as excruciating, in the end it was simply sad. Presidential debates are supposed to be displays of liberal democracy in action, with reasoned argument over policy and values, between two people hoping to represent the American people. What we got last night was, in the blunt words of CNN’s Chief Political Correspondent Dana Bash, “a s***show”.

Even by his own unique standards Trump was almost manically aggressive. Vicious attacks on nearly every aspect of Joe Biden’s record, and accusations that his son Hunter Biden was corrupt, were combined with constant heckling by Trump. Even the debate’s moderator, Chris Wallace a veteran presenter at Fox News praised for his management of a 2016 presidential debate, struggled to get a word in edgeways.

Biden for his part was clearly thrown by the tactic. Faced with Trump’s constant interruptions Biden stumbled early on and seemed tired. Still, when given the time to speak without interruption Biden could be effective, speaking directly to the TV audience and peddling his brand of empathy politics. By the end Biden seemed more in command, more effectively shrugging off Trump’s attempts to talk over him and delivering the talking points he wanted.

A few of Biden’s ripostes may have also hit the mark: “This is not about my family or his family, this is about your family — the American people. He doesn’t want to talk about what you need.” was an effective pivot from Trump’s allegations about Hunter Biden. At other times Biden simply matched Trump in aggression telling him to “shut up” and calling him a “clown” and a “racist”. However, there was no denying Trump set the tempo of the debate.

In terms of issues the flaming mess that Trump’s relentless hectoring created precluded any enlightening discussion of most issues. The six ordered segments – on the Supreme Court, the pandemic, the economy, race relations, law and order, and election integrity – disintegrated into chaos. Still, there were a few bombshells in there.

The biggest came at the end of the debate when Trump refused to commit to honouring the election. While he said he would honour a fair one he would refuse to accept one marked by ballot manipulation. His incessant, and critics say unfounded, claims of mass fraud in mail in ballots made it clear what he expected to be the case. A dodge when asked to disavow white supremacists and militias, followed by a call for the far-right Proud Boys “Stand back and stand by” was another low.

Biden for his part stuck to his talking points when he could. The biggest one was healthcare, which the coronavirus pandemic gave a particular salience. He also fended off attempts by Trump to paint him as a radical, less due to his own energy than the innate implausibility of the claims. Biden has been disavowing radicals on the left the entire campaign and doing it again was no great challenge. As he said, he beat left-wing rival Bernie Sanders in the primaries by a “hell of a lot.” As for the rest he repeatedly emphasised Trump’s basic unfitness for office. A convincing point, but not much in the way of a positive vision was laid out.

So, who won?

A snap YouGov poll found that 48% of voters thought Biden had, and only 41% thought Trump had. A poll of voters conducted by CNN gave it to Biden by 60% to 28%.

That said, neither candidate can be said to have won in a conventional sense. Trump came across as aggressive and unpresidential, hardly the qualities needed to win back wavering voters but this also let him dominate much of the debate. Biden meanwhile cleared the incredibly low threshold the Trump campaign had set up before him with allegations of outright senility and had some good moments, but he hardly came across as vigorous.

An even more important question is whether it matters either way. Most research suggests that presidential debates nowadays have a negligible effect on voter intentions. Indeed, Hillary Clinton was deemed to have won the debates but still lost the election.

Polls also suggest that by now the vast majority of voters have, unsurprisingly given this race’s extreme partisanship, already made up their minds about which candidate they will pick. It seems no coincidence that percentage of people that thought Trump won almost exactly matches his approval rating. Hundreds of thousands have also already cast their ballots, spurred by the pandemic and the election’s urgency. No matter who people decide won or lost the debate the effects will likely be marginal.

Yet, marginal shifts are shifts nonetheless and could make all the difference in the US electoral system. As with last election there is little prospect of Trump winning the popular vote, but that didn’t matter in 2016 with 80,000 votes in three key states (Michigan, Pennsylvania, and Wisconsin) handing him a resounding electoral college victory. Trump will be hoping that in those states he can reconnect with voters this time. In those closely fought states Biden needs to show he takes the concerns of voters more seriously than Clinton did. She fatally took votes for granted there.

With both sides desperate for any edge in an election they see in existential terms one might have hoped they would bring a better game to the first debate. This was a sorry spectacle.