Pakistan, Oct. 17 -- Washington likes to describe its exit from Afghanistan as a closed chapter. The weapons it left behind say otherwise. More than $7 billion worth of American military equipment stayed in the country in 2021, according to the U.S. Special Inspector General for Afghanistan Reconstruction (SIGAR), and years later it is still turning up in the hands of terrorists who kill Pakistani soldiers, police and civilians. U.S. weapons are now strengthening terrorism and eroding stability in Pakistan. That is the result of a U.S. policy failure, and it deserves to be named as one.

Start with how it was left. SIGAR found that the U.S. military kept an uneven record of what it handed over, and that an "abrupt and uncoordinated" withd...