Not far from the nation’s capital a number of years ago, the violent gang MS-13 introduced a 12-year-old runaway to sex trafficking by throwing a dirty mattress on the floor of a mechanic’s garage and requiring her to submit to sex with a line of customers.

Sadly, it was not an isolated incident. As Attorney General Jeff Sessions recently noted, “Gangs seek to profit off of the victimization of others through drug trafficking, extortion, murdering rivals, robbing innocent bystanders and trafficking vulnerable juveniles for sex.”

Too many cities in the United States are infested with criminal gangs. In 2015, the F.B.I. estimated that more than one million members of approximately 33,000 gangs prey upon American neighborhoods. The gangs have one thing in common: They commit violent crimes that terrorize our communities. And gangs increasingly rely on sex trafficking to support themselves.

Gang members show no sympathy for victims. Indeed, MS-13 members proudly repeat their motto, “Kill, rape and control.” Many gangs plumb new depths of depravity in an effort to live up to that motto.