What is the Defense Production Act, and why is President Trump getting pressure to use it to fight coronavirus?

Ventilators. Masks. Gowns. Gloves. Swabs. Health-care equipment large and small — all lifesaving — is in extremely short supply as American hospitals prepare to be overwhelmed by the coronavirus. There’s a national stockpile of medical equipment for such emergencies, and Congress just gave the government money to buy more. But health officials are warning that that is not enough.