The United States has the highest incarceration rate in the world -- about seven times that of Western European nations – and nearly half of all federal prisoners are doing time for drug-related offenses. With just 5 percent of the global population, the U.S. incarcerates about a quarter of its prisoners.

Something has to give, and Holder’s decision to back off of long minimum sentences for non-violent drug offenders with no ties to organized crime is a logical place for him to start.

“The course we are on is far from sustainable,” he told the American Bar Association, in announcing the policy change this week. Agreed.

Holder pointed out that states have already curtailed their prison-building binges, turning instead to treatment and better supervision to address drug offenders. It’s notable that Holder singled out Texas for praise, citing this state’s success last year in reducing the prison population by 5,000 inmates through treatment and parole policies. Taxpayers benefit, and rehabilitated offenders stand a better chance of making a contribution to society.

Coalitions of conservative and liberal activists have been clamoring for that approach in Texas and elsewhere, and it’s good to see the nation’s top law enforcer giving it currency.

Holder is also throwing his support behind bipartisan efforts in Congress to give judges discretion in sentencing low-level drug offenders. Sens. Rand Paul, R-Kentucky, and Patrick Leahy, D-Vermont, have a bill to provide a “safety valve” so judges can impose sentences below mandatory minimums in appropriate cases. These kinds of reforms are headed in the right direction.

Starting with President Richard Nixon’s 1971 declaration that illicit drugs were “public enemy No. 1,” the law enforcement inertia has reached breathtaking proportions. Since passage of tough-on-crime laws in the 1980s and ’90s, state prison populations have quadrupled and the federal system has grown by 800 percent.

Today, the federal government must also reckon with the parade of states passing medical marijuana laws (20 so far) or legalizing personal use of the weed altogether (Colorado and Washington). While pot sales have become regulated commerce in some states, marijuana remains a dangerous Schedule 1 drug in the federal criminal code, creating a lingering policy headache for Holder’s Justice Department.

More mainstream voices are calling for careful reconsideration. Doing his own analysis of the research, CNN’s chief medical correspondent, Dr. Sanjay Gupta, declared last week that the public has been “terribly and systematically misled for nearly 70 years” about marijuana’s dangers and potential benefits.

That’s not Holder’s fight, yet. He is taking on what is within his immediate authority by slowing down the flow of convicts into the nation’s drug gulag.