AP Explains: Transfer of power under 25th Amendment
A police officer blocks a road before President Donald Trump arrives at Walter Reed National Military Medical Center, in Bethesda, Md., Friday, Oct. 2, 2020, after he tested positive for COVID-19. (AP Photo/Jacquelyn Martin)

A police officer blocks a road before President Donald Trump arrives at Walter Reed National Military Medical Center, in Bethesda, Md., Friday, Oct. 2, 2020, after he tested positive for COVID-19. (AP Photo/Jacquelyn Martin)

Oct. 02, 2020 05:56 PM EDT
The helicopter that will carry President Donald Trump to Walter Reed National Military Medical Center in Bethesda, Md., lands on the South Lawn of White House in Washington, Friday, Oct. 2, 2020. The White House says Trump will spend a "few days" at the military hospital after contracting COVID-19. (AP Photo/J. Scott Applewhite)

The helicopter that will carry President Donald Trump to Walter Reed National Military Medical Center in Bethesda, Md., lands on the South Lawn of White House in Washington, Friday, Oct. 2, 2020. The White House says Trump will spend a "few days" at the military hospital after contracting COVID-19. (AP Photo/J. Scott Applewhite)

Oct. 02, 2020 05:37 PM EDT