The 13 U.S. troops killed at Kabul airport’s Abbey Gate in August 2021 were there to help save lives.

It had been four months since then-President Joe Biden ordered the Pentagon to plan for a complete withdrawal of American forces from Afghanistan, and 11 days since Kabul had fallen to the Taliban — a devastating blow to the 20-year U.S. war effort. American troops were helping evacuate tens of thousands of locals, many of whom had been U.S. allies during the war.