For years, the war on drugs has been called a failure. Even the most recent White House drug czar, Michael Botticelli, used his post as the head of America’s war on drugs to repeatedly decry the “old war on drugs” as a set of “failed policies and failed practices.”

But to some drug policy experts, this was all too predictable. Sanho Tree, a fellow at the Institute for Policy Studies who focuses on the war on drugs, argues that the rules of evolution could have helped predict the drug war’s failures — and how the drug war can in fact make our drug epidemics worse.

To understand why, Tree builds on the theory known as the “balloon effect”: Since drugs are always in demand and highly profitable, dismantling one drug trafficking organization doesn’t just extinguish the drug trade that group worked within. Instead, another drug trafficking organization replaces it, filling the same demand that the old group filled. This has happened time and time again throughout the war on drugs; it’s why the drug trade simply moved from Colombia to Mexico after a US-sponsored anti-drug campaign in Colombia, and why the end of one drug trafficking organization in Mexico just seems to spawn another.

One reason for the balloon effect is what experts call the “profit paradox.” One of the primary goals of the drug war is to make drugs more expensive by limiting their supply, the idea being that a drug habit is much more difficult to sustain if drugs are more expensive. But this also makes drugs immensely profitable: They still cost as little as pennies per dose to produce — drugs like marijuana, cocaine, and heroin are just plants or based on plants, after all — while the final street value has to account for the risk of shipping the drug through an international supply chain that can be broken by government authorities at any border.

At the same time, the drug war and risk of capture for drug traffickers do have an insidious effect: It pushes drug trafficking groups to become smarter in how they smuggle drugs. So say a drug trafficking organization ships cocaine or pot through fishing boats, as many typically did in the 1970s and ’80s, but gets caught by the US government. Eventually the government begins doing random checks on all of these boats to make sure none of them have drugs.

But because drugs are still massively profitable and in demand, the organizations that didn’t get caught aren’t just going to give up. They’re instead going to find other ways to smuggle drugs — like cigarette boats and narco-submarines, which drug traffickers make a lot more use of today. The drug traffickers, then, became more efficient in response to drug war policies.

“You get this filtering effect decade after decade where you end up artificially selecting or breeding super-traffickers,” Tree said.

This effect also applies to the kinds of drugs that traffickers trade in. So at first the current opioid epidemic — the deadliest drug crisis in US history — led traffickers to push heroin as a cheaper, more accessible alternative to opioid painkillers, which were increasingly blocked off to recreational users by government-restricted prescriptions.

But over time, drug traffickers have begun to trade more and more in an even more potent (and deadlier) opioid: fentanyl. For traffickers, it made financial sense: Since fentanyl is more potent but is also fairly cheap to produce, traffickers can promise a high at a lower dose, which means they have to smuggle less of the product (making it easier to conceal), for a similar or even greater profit. Concerns about getting caught only made traffickers much more efficient in the drug they trade in, even if it led to trafficking a more dangerous substance.

These types of unintended consequences are why Tree says we should totally rethink the drug war.

Not every drug policy expert agrees with Tree. (See my broader explainer on ending the drug war for some of the counterarguments.) But as someone who has worked on these issues for years, he offers a provocative, thoughtful perspective that challenges much of the federal government’s conventional wisdom on the drug war — and looks for a better way forward.

What follows is my conversation with Tree, edited for length and clarity.

German Lopez

What can we learn from Darwin and evolution about the war on drugs?

Sanho Tree

We’ve basically been thinning out the herd [of drug traffickers] for many decades now [by] going for relatively low-hanging fruit, which is the dynamic you get with bureaucracies and law enforcement. Even if they want to go for high-value targets, they often go for the low-hanging fruit because they can — it boosts their numbers, and it’s much easier to win those kinds of cases, so the metrics all work in their favor.

You get this filtering effect decade after decade where you end up artificially selecting or breeding super-traffickers. The people we tend to capture tend to be the people who are dumb enough to get caught, or people who have violated their own operational security — they stayed on the phone too long, they bribed too much, they engaged in turf wars, they raised a profile, they spent too much money in flashy ways, they screwed up. Those are the people who tend to get captured.

And the people we tend to miss are the ones who are the most adaptable, the most innovative, the most cunning. But not necessarily the most violent. The more successful ones tend to deploy [violence] very strategically rather than an all-out policy of just “kill them all.” If a cartel thinks it can get away with a bribe rather than a bullet, by all means they use the bribe — and I think that’s one of the reasons for their longevity.

German Lopez

What are some good examples of the filtering effect that we’ve seen in recent times?

Sanho Tree

Well, we’ve forced this [drug] economy to evolve at a lightning pace. In some ways, the war on marijuana got [traffickers] to realize there’s something that’s easier to smuggle and more profitable and addictive to some people. That’s why they switched to cocaine from Colombia, rather than marijuana that used to come from Colombia and Jamaica.

So we end up with cocaine very popular in the 1980s. And the war on cocaine helped popularize another substitute — a poor person’s substitute — in crack. And in other ways, our war on crack helped repopularize an old drug — methamphetamines, the “poor person’s crack.”

Each time we end up with a more evolved substance — easier to produce, harder to stop. In that sense, you’re forcing the drug economy to evolve.

In terms of drug trafficking networks, we’ve seen this [filtering effect] at the local level but also at the international cartel levels of who tends to survive. We’ve targeted a lot of the easier-to-stop criminals rather than the ones who are more cunning and more adaptable. You could see that in the cartel wars in Mexico.

But at the end of the day, you’re really shifting turf lines rather than reducing the number of drugs coming through. Turf wars are supposed to have a beginning, middle, and end, but the drug war has prolonged the middle indefinitely — much longer than it needed to last. And it caused a tremendous amount of death and violence that was completely unnecessary, given that the drugs are flowing again. So to what end have we done all of this?

German Lopez

This seems like an extension on the balloon effect. But it’s not just that drug producers or traffickers will pop up when one is taken down, but that the ones that pop up are actually more ruthless and efficient than the producers and traffickers they’re replacing.

Sanho Tree

Exactly. So we go after shrimp boats and fishing boats [used to smuggle drugs] and stop those, and they respond with cigarette boats. We respond with faster boats and helicopters to take out those boats, and then they switch to submersibles. And then we get better at detecting those with spotting towers now, and they go the fully submersible route. And if we do catch those, there are “narco-torpedoes” now; these can be bolted under the hull of a ship with release cables and homing devices.

So we’re causing that economy to evolve at warp speed.

With the border wall, we built a fence, and the countermeasures immediately popped up — whether building a ramp that can drive right up to the fence or using catapults or using drones or tunnels.

We’ve basically set up an exercise for bad guys to find innovative ways to penetrate our borders. That’s not a smart thing to do from the perspective of homeland security. But if you do it right, you can rake in billions.

German Lopez

Drug warriors’ argument is that at least these anti-drug efforts make drugs more expensive, because it disrupts the drug trade, making drugs harder to produce and ship without a “tax” of sorts through the threat of governments taking your product at any moment. The benefit to that is more expensive drugs, which may make it harder for someone to form a drug habit. How would you respond to that?

Sanho Tree

We’ve never been able to price it out of the hands of consumers. Basically anyone who wants drugs can get drugs as long as they’re willing to pay that final street price.

And we’ve never been able to push the price up through either the production side or the trafficking side, because it’s a drop in the bucket of the real wealth that’s built in. The drug snowballs in value as it gets to the actual consumer.

German Lopez

So it sounds like the argument is basically that the drug war might make drugs more expensive, but it doesn’t make the drug expensive enough. Heroin, for example, is still way cheaper than opioid painkillers. And fentanyl is even cheaper than that.

Sanho Tree

Yeah. And you don’t need a prescription. There’s no red tape.

But you’re spinning the roulette [wheel] real bad. You don’t know what you’re getting in that heroin. You don’t know whether it’s 10 percent or 70 percent pure. And now you don’t know if it has fentanyl or other things that were not a problem in the past.

German Lopez

There’s a downside to making drugs more expensive too: You make it more lucrative for people to take part in the drug trade.

Sanho Tree

Exactly.

German Lopez

One other element to this is that taking down big drug cartel bosses can also lead to more violence, because it creates a power void that other traffickers will fight to fill.

Sanho Tree

Absolutely. One of the reasons that, for instance, in the 1980s and ’90s the crack wars were so violent in the United States is not because the crack itself was causing people to become violent. Crack is still out there today, but you never hear about the shootouts and other kinds of things that happened back then.

Part of the reason, instead, was that crack was a new drug, so the turf line hadn’t been established yet. So the knee-jerk but not unreasonable demand by community members was, “Hey, there’s an open-air market in my neighborhood. My daughter can’t ride her bicycle in front of her own house because of stray bullets. I want you to shut it down.” And [police] did that.

And they ended up creating then a vacuum — a job opportunity. If you take a dealer off the street corner, you basically open up a very valuable piece of real estate. I used to watch this in East Baltimore back in the late ’90s when I worked there. You could see tourists coming in from the suburbs into these open-air markets in the city to buy drugs, because that’s where everyone knew you could buy drugs.

You couldn’t just move those types of markets. You can’t put up a billboard or take an ad out in the Yellow Pages: “Go buy your drugs in this corner now.” That doesn’t happen.

So taking someone off that street corner creates a job opportunity, a vacuum, where rival gangs or crews will now come to fight for that void. And they can’t go to a judge and say, “Your honor, I’ve been selling drugs in the city for 15 years, and this is my turf. Please kick them out.” The only recourse is through violence, intimidation, or threats of violence.

German Lopez

What do you take as the lesson from this? What does it teach about the war on drugs in terms of its overall effectiveness?

Sanho Tree

We need to look at motivations. It’s never a good idea to have a policy that amplifies the motivational feedback loop of the adversaries you’re trying to stop. We do that with parts of drug prohibition, we do that with creating more evolved syndicates, we do that with beefing up technologically. All of these things come back to bite us in the end.

From a homeland security point of view, it’s those damn tunnels that worry me the most. There’s no motivation right now for cartels to be working with terrorists. But who’s to say that someday in the future, there’s some tunnel that’s already operating, and there’s a lieutenant who wants to get his beak wet and deliver some packages or people for some shady group, and it turns out that it’s a WMD.

That could be really problematic. We have radiation sensors at checkpoints. But do they work 100 feet underground, in these tunnels? I don’t know.

There is an incentive for them to not get involved in this. Once it’s revealed that a cartel is involved in this, they’ll get the full weight of the US government breathing down their necks. But once again, the technology is there, it’s for sale.

German Lopez

So what are the solutions here? What do you think we should do to deal with all of this?

Sanho Tree

At the end of the day, there is no substitute for building a healthy society.

The legalization and regulation of drugs is a good ultimate objective.

But at the same time, we can’t bury our heads in the sand and pretend that people aren’t living through a great deal of poverty, despair, and alienation. We have to deal with why it is that people choose to self-medicate at relatively high levels compared to other industrialized societies. That involves taking a closer look at how we organize our lives here in the United States.