Nearly 3 million people tuned in to Tucker Carlson’s Fox News show on the evening of June 2, a number equivalent to nearly 1 percent of the country. Among the things those viewers heard from Carlson that night was a staggering accusation of duplicity if not illegality on the part of the country’s top infectious-disease expert, Anthony S. Fauci. Carlson accused Fauci of lying under oath, of lying during a news conference and of being somehow implicated in criminal activity based on the contents of a number of emails released publicly under a Freedom of Information Act request. Those emails...