Two of the most important tests of President Joe Biden’s promise to “end the Forever War” are found not on the battlefields of Afghanistan but inside the cages of Guantanamo Bay.

There, since 2007, the U.S. has caged Asadullah Haroon, sometimes called Haroon al-Afghani, a member of the Hezb-e-Islami, an insurgent group and political faction led by Gulbuddin Hekmatyar, an American ally in the 1980s and enemy in post-9/11 Afghanistan. A year later, Guantanamo caged another Afghan, Muhammad Rahim, the last man known to have experienced CIA torture inside the agency’s black sites.

Haroon and Rahim are the last Afghans among Guantanamo’s 40 detainees. They are informally known as Forever Prisoners—people the military does not charge with any war crime but claims are too dangerous to be free.