The American and allied military presence in Afghanistan peaked between late 2010 and mid 2011. For the next ten years, the major debate in Washington was how many troops to withdraw, how quickly. The announced unilateral American withdrawal was the defining fact of the war for its final decade. Policymakers treated the debate over troop numbers as a proxy for a debate over larger goals. But there are other aspects of strategy, like reconstruction and diplomacy, that simply cannot be subsumed within a debate about troop numbers, aspects that went unaddressed during the US’s gradual withdrawal from Afghanistan. Withdrawing troops without achieving the other objectives is how the United States gradually abandoned the rest of its war aims as slowly and expensively as possible.

Did the surge work? The surge had a major impact on the military situation, reversing the Taliban’s momentum and rapidly growing the Afghan army. Yet it seems equally clear that, by the beginning of the withdrawal in July 2011 – or even by the transition in 2014 – Afghan governance had not improved enough and there was no self-sustaining psychological dynamic of growing optimism and confidence. Importantly, the military surge cannot be evaluated apart from either the civilian surge or the withdrawal timetable because they were components of a single strategy. The civilian surge largely failed, replicating many of the same problems the Bush administration had seen when it tried to ramp up assistance for governance and reconstruction. But even more consequentially, the timetable – the most distinctive aspect of the Obama administration’s war – drove so much of the implementation and the decision-making as to become the controlling dynamic of the war. Together, the timetable and the civilian failure squandered whatever military gains the surge accomplished. By 2011, the insurgency had lost momentum, but the Afghan government was no closer to victory.