Steven Alm, a circuit judge in Honolulu, and Leighton Iles, the probation chief for Tarrant County, Texas (Fort Worth and Arlington), have demonstrated that swift and certain sanctions make all the difference. In a carefully studied yearlong trial involving hundreds of probationers, Judge Alm’s program, called HOPE, reduced drug use by more than 80% and days behind bars by more than 50%, according to figures from the National Institute of Justice. Offenders quickly learned that drug use was no longer something they could get away with, and even most long-term users were able to quit. The program freed them from the cycle of use, crime and incarceration.

Having to call in every day to find out whether it is your day to be tested turns out to be powerful help in staying clean. As one probationer told a researcher, “Knowing I had to make that phone call the next morning ruined the high.” Leighton Iles’s Swift program in Texas has recorded equally impressive results, and there are promising pilot efforts with parolees in Seattle and Sacramento…

David Kennedy of John Jay College in New York City has pioneered two related programs designed to go after the most violent dealers and organizations and to shut down the most violent market areas. His Drug Market Intervention program, first used in High Point, N.C., in 2004 and replicated many times in places such as Hempstead, N.Y., and Memphis, Tenn., focuses on areas where crack houses and flagrant street-corner dealing generate crime and disorder.

The first step, once the police negotiate community support, is to identify all the dealers and make cases against them. Then comes the surprising part: Instead of being arrested, the nonviolent dealers are called in for a meeting. (The handful of violent ones go to jail.) They are presented with the evidence against them—perhaps video of them making a sale—and confronted by angry neighbors, clergy and relatives. Each one is then offered a choice: Stop dealing and get help to turn your life around, or tell it to the judge.