Biden then claimed it is Trump, not him, who has foreign sources of income.
"The guy who got in trouble in Ukraine was this guy," Biden said, speaking of Trump. "The only guy who's made money from China is this guy."
Trump hopes that his performance in the final debate will mark a pivot point in the campaign, making it a race between him and Biden, rather than a referendum on his own presidency. Yet, with nearly 50 million votes already cast, it may all prove to be a gambit better designed for a different campaign, against a different candidate and, perhaps, for a different era entirely.
As he did at the first debate, Biden sought to turn the conversation back to bigger issues. "It's not about his family and my family. It's about your family," he said, speaking to viewers. "And your family is hurting badly."
Despite the microphone muting and the "malarkey" mention, a real presidential debate at times broke out. The discussion focused extensively on the major issues confronting Americans at this moment, with Biden sharpening his tone when blaming Trump for the more than 220,000 COVID-19 deaths in the country.
"Anyone who's responsible for that many deaths should not remain as president of the United States of America," Biden said. "The way the president responded to this crisis has been absolutely tragic."
Trump -- who went in and out of the hospital due to his COVID-19 diagnosis since the last debate -- maintained that a vaccine will be available "in weeks," trying to counter grim realities with optimism.
"More and more people are getting better," the president said. "It will go away, and as I say, we're rounding the turn, we're rounding the corner. It's going away."
Trump also sought to portray Biden as captive to the far left, saying that he would usher in "socialized medicine" and embrace environmental policies that would harm the economy.
But on that, Biden came back to the image he has cultivated for decades in public life and through a long-ago primary season where he avoided being pulled in notable progressive directions.
"He's a very confused guy. He thinks he's running against somebody else. He's running against Joe Biden," Biden said of Trump.
Trump was more disciplined, though he executed verbal attacks on Biden and his family. He sought to come back to why he got into politics, taking on Biden as an insider.
"I ran because of you. I ran because of Barack Obama," Trump said. "I'm looking at you now. You're a politician. I ran because of you."
Biden had a counter that drew on the tumult in the country in the time since he left office in 2017.
"He pours fuel on every single racist fire, every single one," Biden said of Trump. "This guy is a dog whistle about as big as a fog horn."
The race will surely have its share of stunning moments still. This final face-to-face encounter, though, held reminders of why the campaign has moved so little, as time runs out to change perceptions of two well-defined candidates.