On Tuesday afternoon, Joe Biden tried to “turn the page” from a month of chaos and death in Afghanistan and, more broadly, from 20 years of ultimately futile US attempts at occupation and nation-building. He spoke of the “extraordinary success” of the US evacuation mission over the past few weeks, with more than a hundred thousand Americans and Afghans airlifted out under extreme duress. At times he seemed defensive, noting that Americans were warned 19 times to exit Afghanistan before the August US military withdrawal. He accused Afghan leaders, allies on whom the US had depended, of “corruption and malfeasance”....