The most famous scene in Peter Weir’s hit movie, The Truman Show, depicts Truman Burbank’s wife, Meryl — who, unbeknownst to him, is an actress — growing alarmed by her husband’s behavior, breaking the fourth wall in a panic, and shouting, “Do something!” to the producers of the titular show, who are hidden off-set. Obliging her request, the producers immediately dispatch a neighbor — also an actor — to show up at Truman’s front door, deus-ex-machina–style, and defuse the situation. “Who were you talking to?” Truman asks Meryl before the neighbor arrives.

“Who,” indeed?

For more than seven decades now, America’s boundary-pushing …