ar in Iran having failed to materialise and, freshly acquitted by the Senate, Donald Trump was in upbeat form in February 2020.

The only blot on his horizon was the emergence of a deadly new respiratory disease in the city of Wuhan, China, but the president had rejected the significance of Covid-19 out of hand, telling the World Economic Forum in Davos, Switzerland, a day after the first American case had been recorded on 21 January: “We have this totally under control.”

After the World Health Organisation declared a global emergency on 30 January, Trump moved to shut down air travel from China as a precaution and assumed that would be sufficient to block its arrival on American shores.