When I worked in the White House in the 1980s, my boss remarked that I came from a “Mafia town” after I told her I was raised in Cherry Hill, New Jersey. She said the Mob killed John F. Kennedy, as if this was a fact. For decades afterward, I’ve been researching and writing about organized crime, my latest book wrestling with the mythology—and reality—of the Mob and the presidency.

My biggest surprise was the omnipresence of the Mafia in presidential politics for much of the last century. Gangsters acted on an ad hoc basis down the food chain, but for the benefit of presidents when something needed to be done. Quietly—because appearances are everything in America.