Fact-checking President Donald Trump and some Democratic candidates on coronavirus

President Donald Trump has not proved to be the bearer of reliable information when calamity threatens and people want straight answers about it. That's happening again as he addresses the prospect of a coronavirus outbreak in the U.S.

The infectious disease risks not only public health but the economy he holds up to voters for his reelection. To date, his comments have largely seemed intended to put a positive spin on hard information from the scientists, as if he were wishing the problem away. He also called the spread of...