The war has cost the lives of 2,448 American service members and consumed an estimated $2-trillion. US troop numbers in Afghanistan peaked at more than 100,000 in 2011. The Democratic president had faced a May 1 withdrawal deadline, set by his Republican predecessor Donald Trump, who tried but failed to pull the troops out before leaving office in January. Instead, Biden said the final withdrawal would start on May 1 and end by September 11. In withdrawing, Biden is embracing risks at the start of his presidency that proved too great for his predecessors, including that al Qaeda might reconstitute itself or that the Taliban insurgency might topple the US-backed government in Kabul.