Attorney General Michael Mukasey has in most ways been a vast improvement over his predecessor, Alberto Gonzales. But at a time when an unprecedented one in 100 American adults is behind bars — including one in nine black men between the ages of 20 and 34 — he has so far been a big disappointment to those hoping for a change in the lock-’em-up-and-throw-away-the-key policies on nonviolent drug offenders.

Mukasey has resorted to counterfactual fear-mongering in calling for Congress to roll back the U.S. Sentencing Commission’s wise, unanimous decision last year to reduce retroactively the especially cruel and counterproductive prison terms provided by its sentencing guidelines for crack cocaine. The commission’s action has made 19,500 federal prisoners serving crack sentences — more than 80 percent of whom are black — eligible at some point to seek sentence reductions averaging just over two years.

The commission’s decision, which became fully effective on March 3 over Mukasey’s objection, was a step toward slowing the sixfold increase since 1970 in the number of people behind bars in the United States, from 330,000 to 2.3 million, more than in any other nation. The impact of this prison binge on hundreds of thousands of young black drug offenders with (in most cases) no record of violence has been especially harsh. The seven-member commission has also urged Congress to reform the savagely severe federal mandatory minimum sentencing laws for crack.

But Mukasey objected to the retro-active sentence reductions, asserting in a February 25 speech to the Fraternal Order of Police (and on other occasions) that these 19,500 crack offenders "are some of the most serious and violent offenders in the federal system."

This was, at best, a gross exaggeration glaringly unsupported by the statistics that Mukasey cited. So was Mukasey’s earlier suggestion in congressional testimony that the Sentencing Commission’s action would make "many … violent gang members … eligible for immediate release into communities nationwide."

The attorney general omitted the fact that in 2005, 19 out of 20 (94.5 percent) of crack offenses involved no violence and nine out of 10 (89.6 percent) also involved no threats of violence, according to the Sentencing Commission’s authoritative statistics. He also failed to note that only 1 percent of crack prisoners eligible for immediate release were classified as career criminals.

It’s true, as Mukasey stressed, that nearly 80 percent of the crack offenders who might get released before completion of their guideline sentences have prior criminal records. It’s also true that about half were found to have dealt with substantial quantities (over 50 grams) of crack. And it’s further true that for close to one-third of these crack offenders, the courts imposed harsher sentences because they or an accomplice had a gun or other weapon.

Of course, that statistic also means that two-thirds had no weapons at all. And the vast majority of the other one-third (including those whose weapons were unloaded, inoperable, or legal) were street dealers who neither used nor threatened to use their weapons — and who cannot even be considered for possible release until after they have served their time for any weapons offenses.

Nor did Mukasey take into account that no prisoner will be freed early unless and until a federal judge approves his release, after considering any record of violence or threat to public safety and any other objection that prosecutors might have. Instead, the attorney general told the U.S. Conference of Mayors on January 24 that "a sudden influx [of released prisoners into communities] could lead to a surge in new victims."

This is a false alarm. "His position presupposes that judges will be irresponsible in exercising their discretion," as Judge Reggie Walton of the U.S. District Court for the District of Columbia — known for being tough on crime — has said.

In fact, most of the petitions for sentence reductions will be spread out over more than 10 years. The average eligible prisoner is serving a sentence of more than 12 years and could seek an eventual reduction of about 27 months. Most could not seek immediate release.

The commission’s decision "is a modest first step to correct decades of injustice," says Mary Price, vice president and general counsel of Families Against Mandatory Minimums, a sentencing reform group. "Instead of repeating misleading and repudiated claims that will only spread fear, the attorney general should be reassuring communities that the nation’s prosecutors are working to identify and oppose the release of any prisoners who might pose a threat." Drug offenders have lower recidivism rates than violent criminals or any other group of prisoners, Price noted.

The sorry history of crack sentencing is aptly summarized on the website of the Sentencing Project, another reform group:

"The 1986 and 1988 Anti-Drug Abuse Acts established excessive mandatory penalties for crack cocaine that were the harshest ever adopted for low-level drug offenses and created drastically different penalty structures for crack cocaine compared to powder cocaine…. The law has diverted precious resources away from prevention and treatment for drug users and devastated communities ripped apart by incarceration."

The rationale for the differential penalties is that crack cocaine, which is smoked, is cheaper, produces faster highs and lows, and is somewhat more often associated with violence than is powder. Such differences might arguably justify somewhat tougher sentences for crack. But crack is made from powder, the substances are pharmacologically identical, and the onetime clamor over special harm to "crack babies" was off base; studies show that pregnant women who use alcohol and tobacco cause more damage to their children.

The huge crack powder sentencing differentials are wildly disproportionate to any differences in the harms caused. For example, simple possession of 5 grams of crack (the weight of a nickel) brings the same five-year mandatory minimum sentence as selling 500 grams of powder cocaine. That’s why most crack prisoners are low-level street dealers.

The fact that more than 80 percent of crack prisoners and only 27 percent of powder-cocaine prisoners are African-Americans makes the unfairness of the crack penalties especially glaring and feeds the corrosive perception among many blacks that the criminal-justice system is racist.

"Instead of reducing drug addiction and crime," Rep. Charles Rangel, D-N.Y., testified at a February 26 House Judiciary subcommittee hearing, the crack mandatory minimums "have swelled our prisons, fueled a racial divide that jails young black men at disproportionate rates, left a generation of children fatherless, and driven up the costs of a justice system focused more on harsh punishment than rehabilitation."

All this helps explain why so many of those who once supported the harsh crack sentences — among them President Clinton and Sens. Joseph Biden, D-Del., Orrin Hatch, R-Utah, and Jeff Sessions, R-Ala., a passionate drug warrior who supports severe sentences for genuinely dangerous drug dealers — have expressed deep regret and called for reform. Leading tough-on-crime conservative scholars, including James Q. Wilson and John Dilulio Jr., have also called for reforming crack sentencing.

Even President Bush — a reformed alcoholic with a drunk-driving conviction — said in January 2001 that "long minimum sentences for the first-time users may not be the best way to occupy jail space and/or heal people from their disease," and "I don’t believe we ought to be discriminatory" by punishing crack offenders more severely than powder cocaine offenders. But Bush has not had the courage of his convictions.

More broadly, it has long been clear that Congress’s imposition since 1986 of lengthy mandatory minimum prison terms even for bit players has failed to make much of a dent in the drug problem. The kingpins supposedly targeted by these laws rarely get caught. Instead, we spend billions of dollars to warehouse scores of thousands of nonviolent, nondangerous people who made mistakes, and who could become productive members of society if given drug treatment and a second chance backed up by the threat of incarceration if they sell drugs again.

So why is Mukasey, a respected former federal judge who ought to know better, spouting the same tired alarmism about crack defendants that has emanated from the Justice Department for two decades?

Perhaps because a new attorney general with less than 11 months left in office has to pick his battles rather than questioning every dumb Justice Department policy that he inherited.

But this policy is worse than dumb. It is ruining thousands of lives that could be salvaged under a humane sentencing policy. It is decimating black communities. It is undermining confidence in the fairness of the justice system. And it is wasting tax dollars.

Fortunately, Mukasey has not ruled out working with congressional reformers to consider reducing mandatory crack sentences for future defendants. It’s the least he could do to redeem his unpromising start on this vital criminal-justice issue.