In a debate that was the political equivalent of a food fight, the winner was the man who emerged least covered in slop.

On Tuesday night, on the basis of instant polls and betting markets, that man was Joe Biden - if only because his main goal was to prove to Americans that he could hold up under pressure, that he had not lost a step due to his advancing age. He had to show he could take a pie to the face, metaphorically speaking, and keep his cool.

He mostly met that standard, although it was at least in part because Donald Trump, by his constant hectoring and interruptions, seldom gave the former vice-president a chance to say something truly damaging to his own cause.

Twitter Trump - the unconventional, bombastic, insulting and rumour-mongering aspect of this president - was on full display throughout the hour-and-a-half event. Unfortunately for the president, many Americans, even his own supporters, find his social media persona one of his more unattractive attributes.

Trump needed this debate to shake up a race that is tilting against him - and which has been remarkably stable, through economic, health and social adversity.

Nothing about this free-for-all seems likely to alter the dynamics of this contest or change the minds of the one in 10 American voters who say they are still undecided (although perhaps they'll resolve never to watch another one of these).

'Will you shut up, man?'

It was clear early on what kind of "debate" this would be. Donald Trump's objective was to rattle Joe Biden - and he planned to do it by constantly interrupting the former vice-president.

By CBS News's count, Trump cut in on Biden a total of 73 times.

That made for a series of chaotic exchanges, which included Trump questioning Biden's intelligence and Biden calling Trump a clown, shushing him and asking, indignantly, "Will you shut up, man?"

Time and time again, Trump would snipe at Biden, leaving the Democrat laughing and shaking his head.

As moderator Chris Wallace announced that the coronavirus was the next topic and that both candidates would have two-and-a-half uninterrupted minutes to answer, Biden quipped: "Good luck with that."

Moderating this prestigious primetime event may have been the worst job in America on Tuesday night.
Biden's deliberate camera move

The coronavirus was always going to be difficult terrain for the president - and the topic came up early in the debate. Trump had to defend a pandemic response that has resulted in more than 200,000 American deaths. He did so by saying the steps he's taken prevented more deaths and suggesting Biden would have made things worse.

Biden's reply was to talk directly at the camera, asking the viewers if they could believe Trump (polls indicate a majority of Americans disapprove of Trump's handling of the pandemic).
What did voters make of the debate?

Brian Chellgren - an attorney and a conservative-leaning moderate: It was expected to be chaotic, and it was chaotic. Trump controlled the message with more interrupting, talking and controlling. Biden withstood it better than I thought he would. He got a little hot in the collar a few times. I didn't see any big eye-catching gaffes. I thought Biden had a good few periods where he aimed his message directly at the camera and to the public.

Keirsten Greggs - a talent recruiter and a progressive voter: At the end of the day, the loser was really us, the American people. A lot of people were expecting this to go the way that it did.

Joshua Roizman - a recent college graduate voting for Biden: Biden came out on top. He came out with a strong message and I can't tell you enough how much it mattered that he looked into the camera.

Ariel Hedlund - right-leaning independent voting for Trump: I think Trump's strongest point was when he talked about what he accomplished and what he will accomplish. On the other hand, Biden did really well when he spoke directly to the American people but he never gave us details and facts. I must say Vice-President Biden did much better than I expected.

"A lot of people died and a lot more are going to die unless he gets a lot smarter, a lot quicker," said Biden.

In one telling exchange, Trump boasted about the size of his campaign rallies, held outside because that's what the "experts" - with emphasis on that word - suggest. He then said Biden held smaller rallies because he couldn't attract larger crowds.

"People want their places open," Trump said.

"People want to be safe," Biden countered.

That back-and-forth demonstrated a fundamental difference in the way the two candidates view the pandemic and whether the situation is getting better - or worse.
Race, white supremacists and the suburbs

A debate format that lumped together race issues and urban violence led to feisty exchanges that made clear Biden was more comfortable talking about the former, while Trump wanted to discuss the latter.

Biden accused the president of fomenting racist divisions, while Trump swiped at Biden's support for a 1993 anti-crime bill that led to higher incarceration rates for blacks.

Biden would later go on the attack against Trump for saying Democratic-backed housing proposals meant to increase diversity were threatening to destroy the suburbs of American cities.

"This is not 1950, all these dog-whistles and racism don't work anymore," Biden said. "The suburbs are by and large integrated."

He added that the real threat to the suburbs was Covid-19 and climate change.

Trump was offered the chance to directly renounce right-wing violence - from white supremacists and militias. He said he would, but then he didn't, instead telling one far-right group, the Proud Boys, to "stand back and stand by" (an answer the organisation has subsequently celebrated).

Trump then pivoted to attack antifa, a loose collection of anti-fascist activists, and left-wing mobs.

When Biden was asked about whether, as the self-professed leader of the Democratic Party, he had called on the mayor of Portland or the governor of Oregon to take steps to stop the unrest in that city, he demurred, saying he no longer held elective office.

Wallace had given both candidates a chance to cut against their own bases, which can at times be a wise political strategy. Instead, they both dodged and danced.

The death of George Floyd and resulting conversations about institutional racism and police violence led to mass demonstrations the likes of which the US has not seen in decades.

Tuesday's debate shed little light on those history-making moments.

Trump touts his record of getting things done

If there's a message the Trump campaign wanted Americans to take away from this debate - a clip that was tweeted out from the president's account even as the debate was ongoing - it's that Joe Biden had almost half a century in public office to solve the problems facing the country, and those problems are still around.

"In 47 months, I've done more than you've done in 47 years," Trump told the vice-president.

Biden's response came later in the debate.

"Under this president we've become weaker, sicker, poorer, more divided and more violent," he said.

In 2016, Trump successfully ran against Washington and the status quo. Doing so again after sitting in the Oval Office for three and a half years was always going to be a challenge, but the way he might pull it off is by using Biden's longevity in public life against him.

'I'm the Democratic Party, not Bernie'

One of Trump's goals during this debate - and throughout the whole campaign - has been to paint Biden as beholden to the left wing of his party. Biden, in his very first exchange with the president, outlined his defence.

The opening topic for tonight's debate was the Supreme Court, but Biden quickly turned the discussion to the Affordable Care Act - which is at risk because of a pending case before the high court.

Trump tried to accuse Biden of supporting "socialised medicine" and pushing to do away with private insurance, prompting the Democrat to say that wasn't in his plan - and he's the one who won the Democratic presidential nomination.

"I am the Democratic Party right now," he said. "The platform of the Democratic Party is what I approved."

The tactic re-emerged later on, during an exchange on climate change, when Trump tried to tie Biden to the massive spending and regulation proposals in the "Green New Deal" programme embraced by many on the left.

"I don't support the Green New Deal," Biden said. "I support the Biden plan I put forward."

"Oh, you don't?" Trump asked. "Well, that's a big statement."

Biden, in drawing distinction with progressives in his party, seemed confident that his left flank would hold when it was time to vote.
Biden fails to hurt Trump on his 'hidden taxes'

When the New York Times story about Trump's taxes broke on Sunday night, it was viewed as a bombshell - the public was finally getting a look at information the president had, in a break with tradition, withheld for years.

Political analysts and prognosticators wondered how Trump would handle this during the debate.

When the topic came up, however, Donald Trump offered a similar defence to the one he provided in 2016, when he boasted how he knew the tax code better than any previous candidate - and his ability to avoid a larger tax bill was simply his taking advantage of the law.

Biden, for his part, tried to turn the topic into a condemnation of Republican-passed tax reform. While he noted that Trump paid less in federal taxes than schoolteachers, that message - which could have been a powerful attack - got buried in an ensuing scuffle with the president.

If Trump's tax returns have any legs as an issue in this campaign, it won't be because of this debate.
'This will not end well'

The closing segment of the debate was on election security and concerns - presented by both the left and the right - that the election will not be free and fair.

When it came to the details of the discussion, if you can call it that, they mostly revolved around Trump sharing a series of misleading anecdotes that he says demonstrated that mail-in voting, which millions of Americans will rely on this year, is fraught with corruption and incompetence.

"This will not end well," Trump said at one point - a sentiment that many Americans on both sides of the political aisle will agree with, albeit for different reason.

Biden, for his part, tried to take the high ground. He called for all the ballots to be counted and promised to respect the results of the election once a winner had been decided. It seemed he had a few more points to make in conclusion, but Trump interrupted him again and then Wallace announced the debate was over.

It was a sudden end to a chaotic evening that can hardly be called a debate in any traditional sense of the word. These events rarely swing an election one way or another, and this one was such a muddled mess it seems unlikely few minds were changed.

That's probably bad news for Trump, given that one of his real weaknesses has been with suburban woman voters who say they're turned off by the president's sometimes coarse manner.

Then again, if Trump's goal was to turn this campaign into an ugly scrum, leaving voters alienated from the process and uncertain about whether there will be any kind of clarity or resolution at the end, it was an evening's work well done.