2024 election live updates: Crowd gathers for Trump's Madison Square Garden rally

Harris was asked about President Joe Biden's mental state during an interview with NBC's Hallie Jackson on Tuesday.

Asked by Jackson whether she had seen "anything like what happened at the debate night behind closed doors," Harris did not answer directly.

"It was a bad debate. People have bad debates. He is absolutely..."

"Well, that's the reason why you're here and he's not running for the top of the ticket," Jackson responded.

"Well, you'd have to ask him if that's the only reason why," Harris said.

"What do you think?" Jackson asked.

"I am running for president of the United States, Joe Biden is not, and my presidency will be about bringing a new generation of leadership to America that is focused on the work that we need to do to invest in the ambitions and aspirations of the American people."

-ABC News'

President Joe Biden and Sen. Bernie Sanders teamed up Tuesday afternoon at an event in Concord, New Hampshire, to tout a new report showing Medicare enrollees saved nearly $1 billion on their prescription drugs so far in 2024 through the Inflation Reduction Act.

Biden warned that this progress could be undone if Trump wins in November.

"Trump and MAGA Republicans want to eliminate the Inflation Reduction Act, which we're talking about, the big bill which made all these savings possible, raising prescription drug prices again for millions of Americans," he said.

Biden said Trump and the GOP have tried to replace the Affordable Care Act 51 times and mocked the former president for having only a "concept of a plan."

Biden said if Harris isn't elected, Trump will "kick 45 million people off their health insurance," give tax breaks to the wealthiest Americans, get rid of the Department of Education and gut Social Security and Medicare.

"He'll hurt hard-working people," he said.

Harris acknowledged Tuesday that "of course" it is possible that Trump could declare victory before all the votes are counted next month.

"This is a person, Donald Trump, who tried to undo a free and fair election, who still denies the will of the people, who incited a violent mob to attack the United States Capitol and 140 law enforcement officers were attacked, some who were killed," Harris told NBC's Hallie Jackson in a clip of their interview that was released Tuesday afternoon.

Harris said that she and her team "will deal with election night and the days after as they come, and we have the resources and the expertise and the focus" on that scenario.

The Georgia Supreme Court on Tuesday denied an effort from the Republican National Committee to reinstate a series of election rules, including requiring ballots be counted by hand, after they previously were blocked by a lower judge.

The state's high court ruling was unanimous, according to the order.

The lower court judge previously ruled that seven election rules passed by the state's Republican-led Election Board were "unlawful and void." The RNC then appealed, with RNC chairman Michael Whaley in statement saying the judge "exemplified the very worst of judicial activism."

The order from the Georgia Supreme Court on Tuesday said the appeal "will proceed in the ordinary court" once it is docketed.