Face to face: Trump and Biden to meet for final debate

President Donald Trump dances as he walks off stage after speaking at a campaign rally at Gastonia Municipal Airport, Wednesday, Oct. 21, 2020, in Gastonia, N.C. (AP Photo/Evan Vucci)

President Donald Trump gestures from the top of the steps of Air Force One at Andrews Air Force Base, Md., Wednesday, Oct. 21, 2020. Trump is heading to North Carolina for a campaign rally. (AP Photo/Susan Walsh)

President Donald Trump salutes as he boards Marine One on the South Lawn of the White House, Wednesday, Oct. 21, 2020, in Washington. Trump is en route to North Carolina. (AP Photo/Alex Brandon)

Mock debaters perform onstage as preparations take place for the second Presidential debate at Belmont University, Wednesday, Oct. 21, 2020, in Nashville, Tenn. President Donald Trump and Democratic presidential candidate, former Vice President Joe Biden are scheduled to debate Thursday, Oct. 22. (AP Photo/Patrick Semansky)

This image provided by NBC News shows NBC News White House correspondent Kristen Welker. On Thursday, Oct. 22, 2020, Welker is scheduled to moderate the second and last Presidential debate between President Donald Trump and Democratic presidential candidate former Vice President Joe Biden. (NBC News via AP)

A camera operator is seen near his rig during a rehearsal tests ahead of the final presidential debate between Republican candidate President Donald Trump and Democratic candidate former Vice President Joe Biden on Wednesday. (AP Photo/Julio Cortez)

NASHVILLE, Tenn. — President Donald Trump and his Democratic challenger, Joe Biden, are set to square off in their final debate Thursday, one of the last high-profile opportunities for the trailing incumbent to change the trajectory of an increasingly contentious campaign.