It’s true that most individuals incarcerated for a drug offense were sellers, not just users. But as a result of mandatory sentencing laws, judges often cannot make reasonable distinctions between drug kingpins and street-corner pawns. We ought to empower judges to recognize the difference, and to reduce punishment for run-of-the-mill offenders, who are often pursuing one of the few economic opportunities available to them in destitute communities. The single most important thing we can do is provide meaningful work opportunities to the most disadvantaged.

There are already drug courts in many American communities, and studies show they can reduce substance abuse without incarceration. But the criteria for diversion are often unduly narrow, and they screen out substantial numbers of drug users who could benefit from treatment. Equally important, we should not limit our response to those who have been arrested. Part of winding down the “war on drugs” will require making treatment options more widely available, before individuals enter the criminal justice system.

Recidivism is also a serious obstacle to reform. Two-thirds of released prisoners are rearrested within three years, and half are reincarcerated. But many of the returns to prison are for conduct that violates technical parole requirements, but does not harm others. And much of the problem is that the scale and cost of prison construction have left limited resources for rehabilitation, making it difficult for offenders to find the employment that is necessary to staying straight. So we need to lock up fewer people on the front end as well as enhance reintegration and reduce collateral consequences that impede rehabilitation on the back end.

Criminal justice is administered largely at the state level; 90 percent of those incarcerated are in state and local facilities. This means mass incarceration needs to be dismantled one state at a time. Some states are already making substantial progress. New Jersey, California and New York have all reduced their prison populations by about 25 percent in recent years, with no increase in crime. That should be good news for other states, which would reap substantial savings — in budgetary and human terms — if they followed suit. While the federal government cannot solve this problem alone, it can lead both by example and by providing financial incentives that encourage reform.

Ending mass incarceration will not be easy. Opposition will come from rural community leaders who see prisons as economic development, legislators who still respond emotionally to the “crime of the week” and prosecutors who measure success by convictions and incarcerations, rather than by resolving conflict. But the recent tragic police shootings of young black men have, for the moment, focused our attention on the imperative for reform. And state budgetary crises have led many to question the vast resources we devote to holding too many people under lock and key.

Today, at long last, a consensus for reform is emerging. The facts that no other Western European nation even comes close to our incarceration rates, and that all have lower homicide rates, show that there are better ways to address crime. The marked disparities in whom we choose to lock up pose one of the nation’s most urgent civil rights challenges. But we will not begin to make real progress until we face up to the full dimensions of the task.