U.S. Democratic presidential candidate Joe Biden listens to vice presidential candidate Kamala Harris speak during a campaign event at a carpenters union in Phoenix, Arizona, U.S., October 8, 2020.

Supporters cheer at a drive-in event for Democratic U.S. presidential nominee Joe Biden at the Southeast Career Technical Academy in Las Vegas, Nevada, U.S., October 9, 2020.

A Biden supporter looks on as Democratic U.S. presidential nominee Joe Biden makes a campaign stop at the East Las Vegas Community Center in Las Vegas, Nevada, U.S., October 9, 2020.

U.S. Democratic presidential candidate Joe Biden raises his drink at the Barrio Cafe during a small business bus tour while campaigning in Phoenix, Arizona, U.S., October 8, 2020.

Democratic U.S. presidential nominee Joe Biden and his wife, Dr. Jill Biden, disembark from their campaign plane as they arrive at Miami International Airport prior to participating in a town hall event in Miami, Florida, U.S., October 5, 2020.

Democratic U.S. presidential nominee Joe Biden poses for a photo with mariachi entertainers during his visit to the East Las Vegas Community Center to speak about the disproportionate ways the coronavirus disease (COVID-19) has impacted Latinos, during a campaign stop in Las Vegas, Nevada, U.S., October 9, 2020.

U.S. Democratic presidential candidate Joe Biden speaks to reporters as he departs Wilmington, Delaware, U.S., October 8, 2020.

U.S. Democratic presidential candidate and former Vice President Joe Biden looks on during an NBC News town hall event while campaigning for president in Miami, Florida, U.S., October 5, 2020.

U.S. Democratic presidential candidate Joe Biden looks out from the top of the airplane steps as he departs Phoenix, Arizona, U.S., October 9, 2020.

Democratic U.S. presidential nominee Joe Biden turns to running mate, vice presidential nominee Kamala Harris, as they speak to reporters in a hangar after they arrived at Phoenix Sky Harbor International Airport in Phoenix, Arizona, U.S., October 8, 2020.

U.S. Democratic presidential candidate Joe Biden greets members of his staff and the press as he exits his campaign plane after campaigning in Miami, at New Castle Airport in New Castle, Delaware, U.S., October 6, 2020.

Democratic U.S. presidential nominee Joe Biden disembarks from his campaign plane as he arrives at Phoenix Sky Harbor International Airport in Phoenix, Arizona, U.S., October 8, 2020.

U.S. Democratic presidential candidate Joe Biden speaks to reporters as he departs Wilmington, Delaware, U.S., October 8, 2020.

Supporters cheer at a drive-in event for Democratic U.S. presidential nominee Joe Biden at the Southeast Career Technical Academy in Las Vegas, Nevada, U.S., October 9, 2020.

A participant stands forthe playing of the U.S. national anthem during a drive-in campaign event for Democratic U.S. presidential nominee Joe Biden at the Southeast Career Technical Academy in Las Vegas, Nevada, U.S., October 9, 2020.