Donald Trump has decided not to press ahead with his threat to relax social distancing rules. Americans have federal scientists to thank for his change of heart. The president was shocked by their projections of more than 2m American deaths. Even if the US sticks to scientific guidelines, it could face between 100,000 and 200,000 fatalities. Mr Trump can help by fixing the mess in federal procurement.

Three weeks into the US epidemic — and more than two months after scientists rang alarm bells — Washington has yet to add to the country’s tiny stockpile of ventilators and other essential equipment. Hospitals in New York, which is the epicentre, are within days of facing Italian-style decisions on which patients should get priority. Mr Trump has the authority under the Defense Production Act both to order companies to make equipment if supplies are scarce and oversee distribution to where it is most needed. America’s 50 states are competing in a dog-eat-dog fight for resources. Washington must urgently step in to sort this out.

To date Mr Trump’s learning curve has been considerably flatter than the spread of the virus. He needs to do two things straight away. The first is remove any whiff of political bias from federal allocation. Mr Trump all but admitted last week that US states with governors that praised him would be rewarded while those that complained would be punished. “I want them to be more appreciative,” he said. Florida, with a supportive Republican governor, received 100 per cent of the material it requested last week. By contrast, Michigan and Illinois, which both have Democratic governors, each of whom has protested against the slow federal response, received only a fraction of what they needed. This is unacceptable. It is the duty of America’s chief executive to funnel help as rapidly as possible to where it is most needed. At the same time, Mr Trump must stop accusing frontline states of hoarding equipment. It seems he misunderstood New York’s attempts to build a ventilator stockpile in anticipation of rising demand — precisely what Washington has failed to do.