The lessons of Afghanistan

The end of America’s war in Afghanistan has prompted an enormous amount of finger-pointing and second-guessing among U.S. officials seeking to make sense of how a 20-year campaign to build up a stable Afghan government could be all but erased in a matter of weeks by the Taliban.

U.S. involvement in the country — from the initial choice to invade to the swift withdrawal, and everything in between — will surely be debated for a long time. There are also questions about what the end of the war means for the people of...