Speaking briefly to reporters in Philadelphia, Harris criticized Trump for not participating in Wednesday's CNN town hall, which had been the scheduled date for a second debate between the two candidates.

"Yet again, Trump not showing up, refused to be a part of a CNN debate, and clearly his staff has been saying he's exhausted," Harris said. "And the sad part about that is, he's trying to president of the United States, probably the toughest job in the world, and he's exhausted."

Harris also touted two recent endorsements from Republicans: former Congressman Fred Upton of Michigan and Shawn Reilly, the mayor of Waukesha, Wisconsin.

“This continues to be, I think, evidence of the fact that people who have been leaders in our country, regardless of their political party, understand what’s at stake. And they are weighing in -- courageously, in many cases -- in support of what we need to have, which is a president of the United States who understands the obligation to uphold the Constitution of the United States and our democracy,” she said.

-ABC News' Will McDuffie

Wisconsin Democratic Party chair Ben Wikler said he views Green Party candidate Jill Stein as a real threat.

His team is working with the Democratic National Committee on ads calling her a potential spoiler for Trump. Stein is running almost exclusively on an anti-war, pro-Palestinian platform this cycle.

Wisconsin will have a packed ballot -- Stein, Cornel West, Chase Oliver and Robert F. Kennedy Jr. -- will appear on the ballot. RFK Jr. is still fighting to have his name removed, but the latest court ruling keeps it on.

-ABC News' MaryAlice Parks

Democrats in the swing state of Wisconsin are preparing for a recount.

The threshold for a candidate to request a recount there is a 1% vote margin. In 2020, the race was significantly closer than that.

The 2020 recount, which increased President Joe Biden's lead over Trump, was not wrapped up until Nov. 29, but the campaign believes it will be done much quicker this time.

Party chairman Ben Wikler referred to his state as "tossup city," and said, "If every person who cares about Harris winning does everything they can between now and Election Day, we will be OK."

The party says it needs only to win the same number of votes it did in 2020.

-ABC News' MaryAlice Parks

Singer songwriter James Taylor will join Harris' running mate Gov. Tim Walz on Thursday evening for a rally in North Carolina, according to the campaign.

Taylor will perform with his wife Kim and son Henry in Wilmington, North Carolina.

"During the rally, Governor Walz will speak directly to North Carolinians about the power of their voice and their vote and encourage voters across the state to get to the polls early and cast their vote ahead of the November 5th election," the campaign said.

Taylor was scheduled to perform at the Democratic National Convention in Chicago this past summer but was bumped for time.

One of Taylor's best-known songs is "Carolina In My Mind," which has been covered by a number of other artists.

Musical stars have joined Harris and Walz in the final stretch of the campaign. On Thursday, Bruce Springsteen will perform at a Harris rally in Georgia, and on Friday, Beyonce is expected to join her at an event in Houston, sources told ABC News.

Over 21 million Americans have voted early as of Tuesday afternoon, according to data from Election Lab at the University of Florida.

Roughly 7.8 million votes have come in through early in-person methods while the remaining votes -- over 13 million -- have been cast through mail ballots, the data showed.

There is a large showing of early votes in the swing state of Georgia which has seen record early vote turnout since early in-person voting began last week.

As of Tuesday afternoon, more than 1.84 million Georgians, roughly one in four registered voters, have cast their ballot, with over 1.74 million votes cast at early voting polling places across the state according to Georgia's Secretary of State office.

-ABC News' Brittany Shepherd and Ivan Pereira