Democratic vice presidential candidate Sen. Kamala Harris, D-Calif., is greeted by Michigan Lt. Gov. Garlin Gilchrist II before speaking at a campaign event, in Detroit.

Supporters of US President Donald Trump wait in line to hear him speak at a campaign rally, at Hickory Regional Airport in Hickory Regional Airport , N.C.

US President Donald Trump arriving for a campaign rally at Richard B. Russell Airport in Rome, Ga.

Jill Biden speaks to supporters while campaigning for her husband Democratic presidential candidate and former Vice President Joe Biden, during a drive in rally, in Tampa, Florida....

Democratic vice presidential candidate Sen. Kamala Harris, D-Calif., speaks at a campaign event in Goldsboro, North Carolina.

US President Donald Trump gestures to first lady Melania Trump after she introduced him during a campaign rally outside Raymond James Stadium, in Tampa.

Vice President Mike Pence and his wife Karen, cast their ballots during early voting in Indianapolis.

US President Donald Trump gestures to supporters as he arrives for a campaign rally at Phoenix Goodyear Airport in Goodyear, Ariz.

Democratic vice presidential candidate Sen. Kamala Harris, D-Calif., speaks at a campaign event in Las Vegas.

Vice President Mike Pence arrives for a campaign event in support of US President Donald Trump, in Flint, Michigan.

US President Donald Trump speaks during a campaign rally at Pensacola International Airport, in Pensacola, Florida.

People watch from their vehicles as President Donald Trump, on left of video screen, and Democratic presidential candidate former Vice President Joe Biden speak during a Presidenti...

Vice President Mike Pence speaks during a rally in Fort Wayne, Indiana.

US President Donald Trump and Democratic presidential candidate former Vice President Joe Biden participate in the final presidential debate at Belmont University, in Nashville, Te...

Democratic presidential candidate former Vice President Joe Biden speaks during the second and final presidential debate at Belmont University in Nashville, Tenn., with US Presiden...

US President Donald Trump speaks during the second and final presidential debate at Belmont University in Nashville, Tenn., with Democratic presidential candidate former Vice Presi...

US President Donald Trump and Democratic presidential candidate former Vice President Joe Biden participate in the final presidential debate at Belmont University, in Nashville, Te...

US President Donald Trump arrives for a campaign rally at Gastonia Municipal Airport, in Gastonia, N.C.

Vice President Mike Pence speaks during the Make America Great Again Event at Lunken Airport in Cincinnati.

Former President Barack Obama speaks during a campaign event for Democratic presidential candidate former Vice President Joe Biden, in Philadelphia.