Biden’s presidency now hinges on pulling off one of the greatest airlifts in history

The reputational damage — to the United States and this president — may yet be contained, if the Biden administration can rescue Afghans who supported our effort over the past 20 years, and who now wish to leave Afghanistan for fear of the conquering Taliban.

Biden pledged just that on Monday; he said the effort, which has so far included a fresh deployment of 6,000 U.S. troops to secure Kabul’s airport, will be “short in time.” Keeping this promise would indeed constitute a meaningful victory amid an otherwise humiliating setback.

History suggests, however, that Biden can conduct a complete evacuation or a quick one — but not necessarily both — given the unique, and uniquely unfavorable, conditions the United States faces.