The nation’s retreat from a maniacal and misguided mission to arrest and imprison our way out of our illegal drug problem has taken another important step.

A federal commission has voted to allow federal inmates serving time on nonviolent drug charges under harsh mandatory-minimum guidelines to petition the courts to reduce their sentences. As many as 46,000 federal felons, some of whom already have spent substantial time in prison, could have their sentences reduced by an average of two years.

It’s estimated that half the inmates in federal prison are doing time for drug charges, and half of those are nonviolent offenders. Pennsylvania has about 12,100 inmates, hundreds if not thousands of whom could be eligible for reduced sentences. For some, if not all, justice will finally be served.

Earlier this year, the U.S. Sentencing Commission voted to reduce the mandatory-minimum drug-sentencing guidelines for nonviolent drug offenses. After much debate and the initial resistance of U.S. Attorney Eric Holder, it voted unanimously on July 17 to apply the new guidelines retroactively to inmates who are behind bars.

What a cruel irony it would have been to “fix the problem of oversentencing only to deny relief to the thousands who have suffered its consequences,” one advocacy group declared.

The prisoner releases will be delayed a year, until November 2015, to allow prosecutors and judges time to consider whether an eligible inmate is a legitimate candidate for release or could potentially create a public risk.

The Sentencing Commission’s decision will have a profound impact, not only on the individuals who were sacrificed to a failed and discriminatory war on drugs, but to the federal prison system, which will save billions of taxpayer dollars and reduce the overcrowding that prison officials predict could potentially explode into violence.

The commission’s decision is another harbinger that the era of sentencing insanity regarding drug violations is ending.

The crack epidemic of the 1980s unleashed a morally righteous and immorally executed crusade that swelled the prisons with drug offenders of every stripe, including those in possession of inconsequential amounts of marijuana — something that’s now legal in certain parts of the country.

(It’s impossible not to note here that the New York Times recently began an editorial campaign urging the federal government to repeal the ban on marijuana altogether.)

The ineffective war on drugs not only bloated the nation’s prisons, it also resulted in what has been called the new Jim Crow. Although whites and blacks use drugs at about the same rate, blacks are arrested and imprisoned at wildly disproportionate rates, in part because of policing tactics such as “stop and frisk” that focus on inner-city residents.

The racial distortion was starkly evident in the disparity between the sentences for possession of crack, mostly imposed on African-Americans, and cocaine, the identical substance in a different form used more often by whites. The Sentencing Commission substantially mitigated, but didn’t eliminate, the disparity in 2011. It also made that decision retroactive.

Clearly and thankfully, the national hysteria has dramatically ebbed. The trend in public policy is toward a fairer application of justice. It’s uneven, of course, and has a distance to go.

But in a chaotic world in which sanity seems hard to come by, every little bit counts. Every step forward should be noted.

We applaud the U.S. Sentencing Commission.