Charles Lane of the Washington Post notes that 49 percent of people in 1994 said crime was the top problem in the country. This wasn’t a priority of white voters alone. The crime bill had the support of nearly 60 percent of nonwhites. Thirty-nine black pastors signed a letter supporting the legislation, and 10 black mayors urged the Congressional Black Caucus to back it, which most members did.

The bill’s funding of more police officers probably helped, and the emphasis on greater incarceration certainly did as well.

It’s not true, as de Blasio says, that the “crime bill was one of the foundations of mass incarceration.” Incarceration began to increase in the 1970s as the crime wave built, and the crime bill most directly affected the federal system, accounting for less than 10 percent of all prisoners. The bill had incentives for states to adopt so-called truth-in-sentencing laws, but a report by the Urban Institute found it only had a marginal effect.

According to a study by the National Academy of Sciences, the drivers of mass incarceration were increases in prison commitments per arrest and in time served.