It was May 1939, and Elisabeth Broder had a plan to flee Europe, where Nazi Germany was ascendant. She would board a boat to Cuba, where she would be reunited with her boyfriend. They would marry, and immigrate to the U.S. But Broder ended up part of a historical moment in which the U.S. and other members of the international community could have done something to helps Jews fleeing Nazi persecution, but decided not to. She was one of 937 passengers on the German ocean liner St. Louis, which crossed the Atlantic only to be turned away by Cuba, the...