Most of the public policy and criminal justice world has woken up to the calamitous damage wrought by our mandatory minimum drug sentencing laws. That includes voices from left, right, libertarian, and most recently, from Attorney General Eric Holder himself. (Congress is in theory on board as well, although the bill to ease the minimum sentences is getting watered down.)

But there’s one group that still can’t quite see the light. Not coincidentally, it’s the group that most benefits from these laws:

 A group of federal prosecutors is criticizing the Department of Justice’s support for legislation that would soften U.S. drug sentencing policies.

The National Association of Assistant United States Attorneys, an organization representing about 1,300 of the 5,600 federal prosecutors, sent a letter to Attorney General Eric Holder last week objecting to his endorsement of the Smarter Sentencing Act. The bipartisan Senate bill would lighten prison sentences for people convicted of nonviolent drug offenses.

The letter, signed by NAAUSA president and assistant U.S. attorney Robert Gay Guthrie, argues that the U.S. should resist calls to reform its mandatory minimum laws, which require judges to sentence certain drug defendants to lengthy prison terms, even if the judge considers those sentences excessive.

In the letter, Guthrie insists that the “merits of mandatory minimums are abundantly clear,” insisting that they reach “only to the most serious of crimes” and “target the most serious criminals.”

“And foremost,” he adds, “they protect law-abiding citizens and help hold crime in check.”

As former assistant U.S. attorney David Zlotnick told Huffington Post in the same article, mandatory minimums make it much easier for prosecutors to put people in prison. It allows them to overcharge suspects, then use the threat of decades behind bars to coerce the accused into pleading guilty to lesser charges. The “trial penalty” can be a powerful incentive, capable of persuading even innocent people to admit to crimes they didn’t commit.

That assistant U.S. attorneys would object to a reform that would make their jobs more difficult isn’t at all surprising. But given that this is in large part a response to Holder’s comments, and that Holder heads up the Justice Department for which these lawyers work, it’s also an act of open political defiance. It’s similar to the way Administrator Michele M. Leonhart of the Drug Enforcement Administration recently criticized President Obama to a convention of sheriffs, for daring to state — correctly — that alcohol is more dangerous than marijuana. (Most of the sheriffs roundly approved.)

Given that most of the country is now in favor of legal pot and opposes mandatory minimum drug sentences, my guess is that we’ll eventually see these tantrums from Leonhart and the assistant U.S. attorneys as more of a death rattle than a significant push-back against reform. The movement on these issues has been remarkable to watch. It’s easy lost sight of just how far this debate has moved. I recently spent the better part of a year researching a book that looks back at some of the most militant periods of the drug war, in the 1980s and early 1990s. There were times when powerful members of Congress were considering suspending habeas corpus for drug dealers. Some suggested bringing the Marines in to conduct home searches for drugs. One congressman wanted to exile drug users to Midway Island to rehabilitate. Some wanted to make it a federal crime for defense attorneys to accept payment from suspected drug offenders, others for anyone to accept money from someone who might be into drugs, be it a gas station attendant, a dry cleaner or a housekeeper.

The debate now is not about what new draconian laws we should pass. It isn’t even about whether we should reform. The debate today is about how we should reform, and by how much. It’s no surprise, then, that the holdouts from the drug war’s salad days are hanging on for dear life. It’s a worldview that’s rapidly shrinking away.

(More commentary on the assistant U.S. attorneys’ letter from criminal defense blogger Scott Greenfield.)