The 20 Years’ War: America in Afghanistan::

America’s war in Afghanistan successfully killed or captured most of al-Qaeda’s original senior leaders, destroyed their safe haven in Afghanistan, and helped prevent another 9/11-scale terrorist attack in the United States. But alongside those gains are the war’s failings: The Taliban and al-Qaeda reestablished safe haven in Pakistan, the Afghan state is weak and corrupt, the Afghan army is dependent on international support and its continued existence may be in doubt. The Taliban is resurgent, peace negotiations between it and the Afghan government have stalled, and jihadists are celebrating the American withdrawal as a victory for their cause.

These failings stemmed from strategic blunders committed by every commander in chief who…