Sen. Kamala Harris said during an ABC interview broadcast Sunday that President Trump called her "nasty" as a distraction, and Joe Biden also addressed Trump's attacks on him.

Details: In the interview Sunday evening with ABC's David Muir, Biden said of Trump questioning his mental fitness to lead: "Watch me."

  • Addressing Trump calling her "nasty," "a madwoman" and more, Harris said, "There is so much more about what comes out of Donald Trump's mouth that is designed to distract the American people from what he is doing every day that is about neglect, negligence and harm to the American people."

Of note: If elected, Biden would be the oldest president sworn into office at the age of 78. Biden's mental fitness has previously been questioned whenever he stuttered, but he has previously said stuttering isn't to blame for his verbal mishaps.

Go deeper: Other key moments from Harris and Biden's first joint interview 

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Biden on presidential mask mandate: "Our legal team thinks I can do that"

Biden waves as he leaves a hotel in Wilmington, Delaware, on Wednesday. Photo: Drew Angerer/Getty Images

Democratic presidential nominee Joe Biden told reporters in Delaware Wednesday he believes he would have the legal authority as president to issue a nationwide mandate to wear face masks to curb the spread of the coronavirus if needed.

Details: "Our legal team thinks I can do that, based upon the degree to which there's a crisis in those states, and how bad things are for the country," Biden said.

Biden's hardline Russia reset

Photo Illustration: Eniola Odetunde/Axios. Getty Images photos: Mark Reinstein

When he talks about Russia, Joe Biden has sounded like Ronald Reagan all summer, setting up a potential Day 1 confrontation with Russian President Vladimir Putin if Biden were to win.

Why it matters: Biden has promised a forceful response against Russia for both election interference and alleged bounty payments to target American troops in Afghanistan. But being tougher than President Trump could be the easy part. The risk is overdoing it and making diplomacy impossible.

Biden: The next president should decide on Ginsburg’s replacement

Joe Biden. Photo: Drew Angerer / Getty Images

Joe Biden is calling for the winner of November's presidential election to select Ruth Bader Ginsburg's replacement on the Supreme Court.

What he's saying: "[L]et me be clear: The voters should pick the president and the president should pick the justice for the Senate to consider," Biden said. "This was the position the Republican Senate took in 2016 when there were almost 10 months to go before the election. That's the position the United States Senate must take today, and the election's only 46 days off.