The United States mission in Afghanistan was supposed to be straightforward.

Osama bin Laden and his followers did the unthinkable on Sept. 11, 2001, hijacking passenger jets and killing thousands in attacks on buildings that symbolized American power. The public overwhelmingly supported invading Afghanistan, whose ruling Taliban movement had sheltered bin Laden.

The initial strike was quick. Yet American troops and their allies stayed in Afghanistan for another 20 years, even though president after president said it was time to leave and the Taliban regained ground while U.S.-backed forces remained shaky.

On April 14, President Joe Biden finally announced that the U.S. would end its military presence in Afghanistan by Sept. 11, 2021.

I am now the fourth United States president to preside over an American troop presence in Afghanistan. Two Republicans . Two Democrats , Biden said in a speech from the White House Treaty Room the same place where President George W. Bush announced the beginning of the war in 2001. I will not pass this responsibility onto a fifth.

The United States has now completed around 12% of the withdrawal, the Defense Department said in a statement this week.

HuffPost spoke to veterans of the war, including non-Americans who supported the U.S. campaign. They shared their complicated feelings about the end of the war, their doubts about the value of the effort, the friends they made (and sometimes lost) and how it felt to risk their lives for a project that Americans largely seemed to forget.