Is ignoring the pandemic a crime against humanity?

Brazil has the world’s second-highest official Covid-19 death toll, just after the United States, with more than 600,000 fatalities. Manaus, the capital of the state of Amazonas, had a deadly first wave that saw mass graves, and a dangerous second where it ran out of oxygen. Through it all, Brazilian President Jair Bolsonaro downplayed what he once called the “little flu,” dismissed public health measures, and promoted unproven treatments like hydroxychloroquine while undermining proven approaches, like vaccines.

Now some Brazilian lawmakers are trying to hold Bolsonaro and his associates accountable. A Senate committee will vote Tuesday on a...