Yet both Ida and the messy departure from Afghanistan pale in comparison to the worst challenge facing a presidency that has never experienced a normal day. Dr. Anthony Fauci, the government’s top infectious diseases specialist, said it was possible that a new University of Washington forecast of a possible 100,000 more US Covid-19 deaths by December 1 could be borne out.

“Unfortunately, it certainly is. You know, what is going on now is both entirely predictable, but entirely preventable. And you know, we know we have the wherewithal with vaccines to turn this around,” Fauci, director of the National Institute of Allergy and Infectious Diseases, said on CNN’s “State of the Union” on Sunday.

Few presidents of the modern era have faced simultaneous emergencies of such magnitude after grueling months that stretched the new administration and a nation exhausted by the worst public health crisis in a century.