Trump’s newly empowered foreign policy led to the Doha agreement with the Taliban and America’s final defeat in Afghanistan. The Taliban’s principal demand and the central element of the eventual Doha agreement was the full withdrawal of US forces from Afghanistan. It was hardly something the Taliban needed to demand because Trump was demanding it too. Trump was not inclined to enforce the agreement anyway. Trump campaigned on getting out of Afghanistan and repeatedly and publicly announced his intent to withdraw, which undermined negotiations just as much as Obama’s timetable had done.

In late 2006 and early 2007, the Bush administration recognized that Afghanistan was deteriorating sharply and undertook a series of strategy reviews. The reviews led to more troops and a new counterinsurgency strategy with attention to training Afghan security forces and improving governance, reconstruction, and counternarcotics. As in 2003, the new approach ran into the buzzsaw of bureaucracy, the fog and friction of war, unanticipated challenges, and, now, a far stronger and more resilient enemy. The problems with the American war effort in 2007 and 2008 were less problems of strategy than of implementation. Having blundered badly in the early years and created huge problems for itself, the American effort was now playing catch up, trying to adjust rapidly to a deteriorating situation.

Some common themes emerge from these lessons about strategy and bureaucracy. The statesman and strategist also need wisdom to take the long view, prudence to discern what is practical, persistence and fortitude in implementation, courage to overcome groupthink and pride and bureaucratic resistance, temperance and humility to toil in unglamorous details. Above all the strategist must have a passion to pursue justice and peace. Statesmen and stateswomen need wisdom, courage, temperance, and justice. If that is true, such timeless principles do not apply only to the individual policymaker. They apply to the nation we serve. American foreign policy should be characterized by wisdom, courage, temperance, and justice; our role in the world should serve those principles. Our grand strategy should take the long view, be practical and aware of our limits yet also courageous and visionary, fearless and uncompromising in the face of obstacles. Above all it must aim at justice – which means it must serve American interests, but it must do so with an awareness of how our interests are entwined with others.

The Bush administration faced three major strategic choices between September 11 and October 7, when the military campaign started: how to define the war, what to do about the Taliban, and what kind of military footprint to deploy. The administration chose to frame the conflict as a War on Terror, to treat the Taliban as of secondary importance, and to adopt a light footprint. The first choice – to declare a War on Terror – has been the subject of ample and justified criticism, then and now. The latter two choices made more sense at the time, and the Taliban’s fall from power two months later, on December 7, seemed to vindicate the administration’s impressive improvisation. But the sense of vindication also numbed the administration to the need to adapt as circumstances changed.