text: FILE - In this Sept. 11, 2011 file photo, a U.S. Army soldier walks past an American Flag hanging in preparation for a ceremony commemorating the tenth anniversary of the 9/11 attacks, at Forward Operating Base Bostick in Kunar province, Afghanistan. After 20 years of military engagement and billions of dollars spent, NATO and the United States still grapple with the same, seemingly intractable conundrum — how to withdraw troops from Afghanistan without abandoning the country to even more mayhem. President Joe Biden is reviewing his predecessor's 2020 deal with the Taliban, which includes a May 1, 2021, deadline for a final U.S. troop withdrawal. (AP Photo/David Goldman, File