In the spring of 2020, when masks abruptly became a common sight in the United States, they introduced a new element into our social relations. They hampered our ability to communicate, muffling our voices and hiding our smiles.

The defendant was a gray-haired grandmother. In the courtroom in downtown Brooklyn, she sat silently as the prosecutor, James E. Wilkinson, read aloud a document she had written—a document that, according to the indictment, was “obscene, lewd, lascivious and filthy, vile and indecent.

In 2004, Heather Hoff was working at a clothing store and living with her husband in San Luis Obispo, a small, laid-back city in the Central Coast region of California. A few years earlier, she had earned a B.S. in materials engineering from the nearby California Polytechnic State University.