China unleashed Covid-19 on an unsuspecting world. It knew by early January 2020 (if not by December 2019 or earlier) that it was dealing with a vicious, fast-spreading disease in Wuhan, a city with more people than Chicago and New York City combined. But first it said nothing. Then it lied repeatedly, expelled foreign journalists, and threatened, silenced or “disappeared” Wuhan doctors who tried to warn the world.