It is easy to forget now, but between 1960 and 1990, the United States experienced perhaps the worst crime wave in its history. Violent crime increased more than 350 percent. Across the 1960s, robbery rose 500 percent in cities with a population of a million. It would be impossible for the political system not to respond vigorously to such a tide of disorder, especially when the criminal-justice system was initially so inadequate to the task.

In his book The Rise and Fall of Violent Crime in America, Barry Latzer notes how the criminal-justice system was fraying as crime spiked in the late 1960s: “The number of arrests per reported crime went down, not up; sentencing to prison occurred less often, not more; and prison time served for serious crimes actually shortened, not lengthened.”

Subsequently, we readjusted, and it wasn’t an exercise in quasi–white supremacy. From 1976 to 2005, blacks were 47 percent of murder victims. Bill Clinton’s talk of kids wasn’t just pulling at the heartstrings. During the crack epidemic in Washington, D.C., about 500 kids were shot and stabbed in a roughly two-year period. Since their communities suffered so grievously from drug crime, black Democrats supported important legislative elements of the crackdown on drug offenses from the 1970s onward.

Yet the war on drugs wasn’t the main driver of the remarkable 30-year rise in incarceration, from roughly 300,000 to more than 1.6 million. According to John Pfaff of Fordham Law School, less than 20 percent of the inmates in state prisons (they house most U.S. prisoners) are there primarily on drug charges. The vast majority are guilty of violent or property offenses.