Sincere marijuana reform question: exactly what are DEA officials "scared" of?

The question in the title of this post, which I am now posting to all the blogs in which I now participate, is my sincere reaction to this new Washington Post article headlined "DEA operations chief decries legalization of marijuana at state level."  Here is the context:

The chief of operations at the Drug Enforcement Administration on Wednesday called the legalization of marijuana at the state level “reckless and irresponsible,” warning that the movement to decriminalize the sale of pot in the United States will have severe consequences.

“It scares us,” James L. Capra said, responding to a question from a senator during a hearing focused on drug cultivation in Afghanistan.  “Every part of the world where this has been tried, it has failed time and time again.”

Capra’s comments marked the DEA’s most public and pointed criticism of the movement toward decriminalization in several states, where local officials see it as an opportunity to generate tax revenue and boost tourism....

Capra said agents have watched the early days of legal marijuana sales in Colorado with dismay.  “There are more dispensaries in Denver than there are Starbucks,” he said.  “The idea somehow people in our country have that this is somehow good for us as a nation is wrong.  It’s a bad thing.”

Capra said that senior DEA officials have faced uncomfortable questions from law enforcement partners abroad. During a recent global summit on counter-narcotics in Moscow, he said, he and the head of the DEA were at a loss to explain the loosening drug laws. “Almost everyone looked at us and said: Why are you doing this [while] pointing a finger to us as a source state?” he said. “I don’t have an answer for them.”...

Capra said he worries about the long-term consequences of the national mood on marijuana, which law enforcement experts call a gateway to more dangerous drugs. “This is a bad experiment,” he said.  “It’s going to cost us in terms of social costs.”

Let me begin by saying I respect all those who work in the DEA and other law enforcement agencies dealing with illegal drug issues, and I am certain all those who do this work have much more first-hand knowledge of the myriad harmful social costs of drug use and abuse than I ever will.  But it is for that very reason that I ask this question about exactly what has DEA officials "scared": I sincerely want a much better understanding of what "social costs" of reform are being referenced here so that I can better assess for myself how I think these potential "social costs" of state-level marijuana reform stack up to the existing "social costs" I see due to current pot prohibition laws and norms.

That said, I think I might be able to help DEA officials avoid "being at a loss" to explain loosening drug laws in the US to their international friends in Moscow or elsewhere.  Here is what I suggest DEA officials say: "The United States of American is an exceptional nation that, in President Lincoln's words, was "conceived in Liberty" and its citizens recently have become ever more skeptical about the growth of government's coercive powers and ever more concerned about paying high taxes for government programming perceived to be ineffectual.  Thus, just as the people of America were the first to experiment seriously with a constitutional democracy (which has worked out pretty well), now some of the people of America are eager to experiment seriously with a regime of marijuana regulation rather than blanket prohibition."

This account of why polls show ever greater support for marijuana legalization is my sincere understanding of why so much drug reform activity is going on now in the United States.  The current "Obama era" is defined by a period of relatively tight budgets, relatively low crime, and yet still record-high taxing-and-spending in service to criminal justice programming.  These realities, especially in the wake of the Tea Party movement and other notable libertarian responses to the enormous modern growth of state and federal governments, have more and more Americans thinking we should be open to experimenting with a regime of marijuana legalization and regulation rather than blanket prohibition.

It is quite possible, as the DEA official suggests, that "this is a bad experiment."  But even if it is, the experiment does not "scare" me, in part because I have a hard time fully understanding what potential increased social costs should make me or others truly "scared."  More importantly, I have enormous confidence that, if the social costs of marijuana reform prove to be significant, the American people will realize pot reform is "a bad experiment" and will again change its laws accordingly. Indeed, this is precisely the experiences we have seen with our legal experiments with other drugs throughout American history:

• roughly 100 years ago, we experimented with national alcohol Prohibition, but thereafter discovered this was bad experiment due to a variety of social costs, and then went back to a regulatory regime for this drug, and have in more recent times kept tightening our regulatory schemes (e.g., raising the drinking age from 18 to 21), as drunk driving and other tangible social costs of alcohol misuse have become ever more evident;

• roughly 50 years ago, we experimented with nearly everyone have easy access to, and smoking, tobacco nearly everywhere, but thereafter discovered this was bad experiment due mostly to health costs, and then have been on a steady path toward ever tighter regulation and localized prohibition (e.g., The Ohio State University just became a tobacco-free campus), as lung cancer and other health costs of tobacco use have become ever more evident.

I emphasize these historic examples of American drug experimentation because it is certainly possible to lament the harms produced along the way or the enduring "social costs" of having tobacco and/or alcohol still legal.  But it is also possible to conclude, as I do, that what makes America both great and special — dare I say exceptional — is that we persistently maintained our fundamental commitments to freedom, democratic self-rule and the rule of law throughout these experiments.  Consequently, this modern era's new round of American drug experimentation has me excited and intrigued to watch unfold the next chapter of the American experience, and I am not "scared" by the marijuana reform movement because they it strikes me as a further vindication of our people's fundamental commitments to freedom, democratic self-rule and the rule of law.

But maybe I am just way too high on the idea of American exceptionalism to have a sensible and sober understanding off all the potential harms and "social costs" that are apparently scaring DEA officials. And, as I said above, I readily acknowledge that all those who work on the front lines of the drug war have much more first-hand knowledge of the myriad harmful social costs of drug use and abuse than I ever will.  But, again, that it why the question in the title of this post is sincere: I genuinely and really want to have a much better understanding of what has DEA officials "scared" so that I can sensibly temper my excitement and optimism about modern marijuana reforms.

I fear that responses to this post could become snarky or ad hominem real quickly, but I hope all readers will tap into the spirit of my inquiry and really try to help me understand just what potential social costs of modern marijuana reform could lead those in the know to be "scared" as the quote above suggests. And I am posting this query in all five blogs I work on these days because I am eager to get wide input and as many diverse insights on this question as possible.