How to prevent a Holocaust

On "The U.S. and the Holocaust," Tom Stoppard's "Leopoldstadt," and living with—and without—history.

When people talk about whether the United States could have intervened to stop the Holocaust, the question is usually a military one: should we have bombed the supply routes to Auschwitz, for instance. But in The U.S. and the Holocaust, the documentary that aired on PBS last fall and is now streaming, Ken Burns and his team ask it differently. What if A…