Joe Biden and Bernie Sanders squared off in what could be the last debate of the Democratic presidential primary.
There wasn't a studio audience because of coronavirus fears, and the outbreak dominated the two-hour sparring match between the two men who want to be Donald Trump's opponent.
Here are five key moments.
1. A woman will be the Democratic running mate
Joe Biden took the leap first and committed to naming a woman as his vice-presidential pick if he becomes the nominee.
Biden declined to list any candidates he was already considering, but suggested Stacey Abrams (who ran for governor of Georgia in 2018), former deputy attorney-general Sally Yates and Maggie Hassan and Jeanne Shaheen (senators from New Hampshire) were the kinds of people he was looking for.
Sanders didn't go quite that far, but said "in all likelihood", he would pick a female VP too.
It's an important milestone in a Democratic race that started as the most diverse in history, but winnowed to a battle between two white men in their 70s.
But despite at least a guaranteed gender-balanced ticket, there will still be questions for the Democratic party to answer once 2020 is done about why women and Americans of colour couldn't succeed in this presidential primary.
2. A Biden cough was a reminder of how large coronavirus looms
Biden got the first question of the debate. He got two words into his answer before he coughed.
As Sanders got his chance at a response, Biden coughed again.
The former vice-president doesn't have coronavirus. And both septuagenarian candidates got the chance to explain to the American public what precautions they'd been taking to protect themselves.
But it was a quick, and sharp, reminder that the coronavirus outbreak was the only thing on America's mind right now. The first 45 minutes of the debate featured questions devoted entirely to the outbreak and the Trump administration's response, and the issue found its way into just about every other topic as well.
It's slowly becoming clear that Americans won't just be voting on Sanders or Biden's hypothetical response to coronavirus right now.
If one of these men wins the White House in November, they could either still be dealing with the outbreak, or managing the nation's economic and emotional recovery.
3. Bernie had the receipts. We already know it won't be enough
Sanders needed a knockout punch in this debate.
His campaign is threatening to collapse after two bad days at the ballot box, and his options for a comeback are shrinking.
Sanders tried to pin Joe Biden on a series of issues including social security, the Iraq war and abortion. He was well prepared, and Biden didn't have completely convincing answers.
But we already know voters aren't being swayed by the airing of Biden's dirty laundry.
Biden has been hit with these lines from the candidates who have dropped out. He's been hit with these lines from Sanders before. His record in office is long and extremely public.
On Super Tuesday, and its sequel a week later, Democratic voters took all that into consideration and still voted in droves for Joe Biden.
4. Biden was Biden. Shaky at times, but no huge blunders
The former vice-president's job at this debate was simple. Keep calm, don't take the bait from Sanders's attacks, avoid any major blunders.
Like in almost every other debate, Biden struggled to nail his key points. There were several questions where his answers were confusing. He was nearly tempted into a shouting match with Sanders on several issues. He didn't deliver many succinct and inspiring soundbites.
But that's been the story of Joe Biden this entire primary season.
He didn't outright win the debate tonight, but he certainly didn't lose it. And given that he's in a dominant position in this race to become Donald Trump's opponent, that's enough.
5. This was probably the last Democratic debate
The next group of voters heads to the polls on Wednesday AEDT. The states that are voting are delegate-rich, and are not favourable for Bernie Sanders.
If the senator from Vermont has another bad day, the calls for him to drop out will be deafening. There isn't another debate scheduled, and there might not need to be unless Sanders mounts a miracle comeback in the next few days.
Even if he does, the coronavirus outbreak could spell an end to the televised debates as we know them for this campaign.
America's Centers for Disease Control recommends avoiding events of 50 people or more for the next eight weeks. Holding debates in packed television studios as the American public is told to avoid restaurants and bars won't just be a bad look, it could be impossible as new rules come into effect.
It's not the first time the coronavirus has upended the norms of an already extraordinary campaign to choose America's next president. It won't be the last.
Catch up on the debate in our blog below.
