The coronavirus pandemic may feel like a past-tense phenomenon for many Americans, even though the dangers are real and ongoing. But a federal judge appointed by Donald Trump just did everything she could to send the nation back into chaos. On Monday, Judge Kathryn Kimball Mizelle in Florida threw out the Centers for Disease Control and Prevention’s mask mandate for air travel and other forms of mass transportation. Deaths from COVID-19—and the mask mandates intended to prevent them—may be on the wane nationwide, but whatever you think about such policies, this is the latest and most egregious example of a...