Attorney General Eric Holder on Monday rightly hailed states that have led the growing national movement to reform the criminal justice system and relieve prison overcrowding as he put the U.S. Justice Department firmly behind efforts to achieve the same goals for federal prisons.

Decrying the fact that nearly half the federal prison population is in jail for drug-related crimes, Mr. Holder told the American Bar Association that U.S. attorneys in the future will use discretion in making charges against “certain low-level, nonviolent drug offenders who have no ties to large-scale organizations, gangs, or cartels” so that they “will no longer be charged with offenses that impose draconian mandatory minimum sentences.”

He also announced Justice Department support for pending bipartisan legislation in Congress to reform criminal sentencing policies, and said the Justice Department will support efforts to reduce repeat offenses by offering better support to discharged prisoners.

Mr. Holder praised efforts in Texas, Arkansas, Kentucky and several other states for reducing prison populations through similar reforms.

He should have mentioned South Carolina as well. According to Justice Department figures, prison populations in South Carolina fell by about 3 percent a year between 2009 and 2011.

That outcome, which has already saved our state more than $175 million in prison construction and operating costs is thanks to a 2010 law that put our state “at the forefront of states advancing research-driven criminal justice polices,” according to the Pew Center on the States.

The law strengthened penalties for violent crimes, but offered alternative approaches for dealing with non-violent offenses, including drug possession. It has led to further reforms in the state’s probation system aimed at reducing the number of probationers returned to prison for technical violations that could be better handled through alternative approaches.

Such state-centered reforms offer a greater promise of correcting the worst abuses of the criminal justice system than do Attorney General Holder’s new policies, however well-intentioned. That is because state prisons hold six times as many inmates as the federal prison system. The drug offenders in the federal system, for example, represent only about 25 percent of the total number of drug offense prisoners in the nation.

We welcome the attorney general’s desire to advance criminal justice reform at the federal level.

But the center of the reform movement remains with state governments, as it should. South Carolinians should be proud of the state’s leadership role in this effort.