Attorney General Eric Holder on Monday announced that certain nonviolent drug offenders would not face mandatory minimum sentences, instructing federal prosecutors not to charge low-level drug dealers with crimes typically subject to more severe punishment.

“Certain low-level, nonviolent drug offenders who have no ties to large-scale organizations, gangs, or cartels will no longer be charged with offenses that impose draconian mandatory minimum sentences,” Holder told the American Bar Association at their annual conference in San Francisco. “They now will be charged with offenses for which the accompanying sentences are better suited to their individual conduct, rather than excessive prison terms more appropriate for violent criminals or drug kingpins.”

Long a central tool in the government’s war on drugs, mandatory minimum prison sentences limit judicial discretion for reducing penalties.

Holder outlined the plan as part of a comprehensive prison reform package, which also includes a call to reduce the elderly population at prisons nationwide.

Holder’s announcement highlights an increasingly aggressive stretch for his Justice Department, following his recent denouncement of Stand Your Ground laws — in the wake of the Trayvon Martin verdict — and pledge to challenge any changes to state voting statutes after the Supreme Court struck down the centerpiece of the Voting Rights Act.

And like those recent cases, Holder framed mandatory minimum sentences as a racial problem.

“We also must confront the reality that — once they’re in that system — people of color often face harsher punishments than their peers,” Holder said. “This isn’t just unacceptable — it is shameful.”

Under laws passed in the 1980s, punishment for crack cocaine was made far stricter than for powder. Critics argue that such a law targets minorities, who are more likely to get caught using the cheaper drug.

The nation’s top lawyer said that U.S. attorneys are crafting guidelines specific for their jurisdictions, which would dictate when federal charges should be pursued.

“Some statutes that mandate inflexible sentences — regardless of the facts or conduct at issue in a particular case — reduce the discretion available to prosecutors, judges, and juries,” Holder said. “They breed disrespect for the system. When applied indiscriminately, they do not serve public safety. They have had a disabling effect on communities. And they are ultimately counterproductive.”

Although Holder said the federal government should focus more on violent crimes than petty drug offenses, he never called for the decriminalization of marijuana, which some have been pressing the administration to do.

In addition to the unilateral actions, the Obama administration is pushing Congress to pass a law that would give federal judges more leeway in when to apply mandatory minimum sentences. Such a bill has a group of bipartisan supporters, including Sens. Rand Paul, R-Ky., Mike Lee, R-Utah, Dick Durbin, D-Ill., and Patrick Leahy, D-Vt.

Leahy will hold a hearing on mandatory minimums in September, kick-starting the debate on Capitol Hill.

“I have come to believe … that our reliance on mandatory minimums has been a great mistake, and I am encouraged that Attorney General Holder and the Department of Justice have joined the growing chorus from across the political spectrum that question this one-size-fits-all approach,” Leahy said on Monday. “It does not make us safer.”

Administration officials expect at least some Republican support because such reforms could produce billions of dollars in savings for the federal government. Some GOP lawmakers, however, would have to be persuaded that such a move would not harm public safety.

According to the Justice Department, federal prisons are now 40 percent overcapacity — and more than half of all inmates are serving time for drug-related crimes. Holder said that both he and his surrogates would travel the country in coming weeks to promote the plan.