For example, even as 3M was producing at 100 percent of its capacity (35 million N-95 masks a month), a single hospital in New York City used up more than two million masks in February, before the surge in Covid-19 cases there. And new production won’t happen for many months.

If you can’t make nearly enough masks to meet the need, then you must conserve the masks you can make. Unfortunately, some hospitals in the United States are not employing science-based methods for conserving these invaluable lifesaving masks.

Making ventilators — machines that breathe for patients who cannot effectively do so on their own — poses an even more formidable challenge. For example, a Medtronic ventilator has about 1,500 parts, supplied by 14 separate countries. More machines might, at best, be manufactured by the hundreds a month — but not by the thousands, as is needed right now.

It is precisely in the face of such hard truths that a national strategy and leadership are crucial. Otherwise, hospitals, governors and politicians will only vie against one another in the reasonable service of their own constituencies.

“Respirators, ventilators, all of the equipment — try getting it yourselves,” Mr. Trump said on a recent conference call with governors. “We will be backing you, but try getting it yourselves. Point of sales, much better, much more direct if you can get it yourself.”

This is exactly the wrong message. The White House must take charge, keeping track of national inventory, purchasing the precious resources and distributing them where they are most needed at the moment. As Andrew Cuomo, the governor of New York, has suggested, ventilators could then be redistributed as outbreak hot spots shift around the country.

More than anything, what the United States needs right now is for the president to undertake an intellectual Manhattan Project: gather the best minds in public health, medicine, medical ethics, catastrophe preparedness and response; political leadership; and private-sector manufacturing and the pharmaceutical industry.

It took nearly three years to develop the atomic bomb. The effort against Covid-19 will need to be bear fruit within days — and come up with a comprehensive but realistic blueprint for getting America through the next 12 to 18 months, or however long it takes for a vaccine to become widely available or herd immunity to take hold in the population. Once a plan has been devised, the president will have to dispense with any happy talk and instead actually convey what the experts are telling him. He will have to define the new normal for a frightened nation that is looking for facts, direction and a common purpose.

Michael T. Osterholm is director of the Center for Infectious Disease Research and Policy at the University of Minnesota. Mark Olshaker is a writer and documentary filmmaker. They are the authors of “Deadliest Enemy: Our War Against Killer Germs.”

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