Mr. Biden believes that further expending U.S. resources in Afghanistan is “a recipe for being there indefinitely.” He rightly notes that President Trump had left him few good options by making a terrible deal with the Taliban. That’s a fine argument, but it explains neither the hastiness nor the consequences we are now observing: the Taliban overrunning swaths of the country, closing in on Kabul, pushing the Afghan security forces and government to the brink of collapse and prompting the Pentagon to prepare for a possible evacuation of the U.S. embassy.

A responsible withdrawal needed more time and better preparation. History will record Mr. Biden, a supposed master of foreign policy for decades, as having failed in this most critical assignment.

As U.S. military planners well know, the Afghan war has a seasonal pattern. The Taliban leadership retreats to bases, largely in Pakistan, every winter and then launches the group’s fighting season campaign in the spring, moving into high gear in the summer after the poppy harvest. At the very least, the United States should have continued to support the Afghans through this period to help them blunt the Taliban’s latest offensive and buy time to plan for a future devoid of American military assistance.