To combat the opioid crisis, the Trump administration is calling for drug dealers to face tougher penalties, including capital punishment in some cases. The U.S. Sentencing Commission is also considering proposals for tougher prison sentences in crimes involving fentanyl, a synthetic opioid that is many times more deadly than heroin. “If we don’t get tough on the drug dealers,” the president said in a recent speech, “we’re wasting our time.”

But Trump’s position — that cracking down on dealers will help users — is contradictory, according to people who work closely with users and researchers who study drug markets. Harsher policies have largely been ineffective in the past at curbing drug supply or consumption, according to most research. But the experts say that when trying to separate users from dealers, a tougher approach will only exacerbate the problem: Sellers and users are often the same people.

Louise Vincent is the director of the Urban Survivors Union, a coalition of active and former drug users based in Greensboro, North Carolina, and has herself straddled the line between user and seller. She grew up around substance abuse, battled addiction and mental health disorders, and faced a charge of possession with intent to deliver. “When I was struggling in my life and surrounded by drug-using lifestyles, part of survival is selling drugs,” she told me. Vincent lost her daughter to an overdose after sending her to treatment. “My life has been shaped by drug policy,” she said.

Vincent now works to support outreach for overdose prevention and harm reduction, and her union operates clean syringe exchange services. According to her experience, it’s harmful to make the distinction that “drug dealers need to go to prison and the drug users are victims,” she said. “Not everyone who sells drugs uses drugs, but I think just about everybody that uses drugs has probably sold drugs or at least hooked up a friend.”

There’s no way to put a definitive number on how many drug users also sell drugs. For starters, users aren’t generally forthcoming about their habit. The most recent results from the Substance Abuse and Mental Health Services Administration’s National Survey on Drug Use and Health, which asks respondents to self-report their drug use, estimated that 475,000 Americans over the age of 12 were current heroin users as of 2016. But household surveys often underestimate illicit drug use because of the stigma attached with the behavior, among other reasons. Dealers are probably even less inclined to report their activities, so quantifying users who also sell drugs is extra difficult.

Instead, organizations like Vincent’s help researchers connect with these communities to better understand and describe them. “It’s a minority method,” said Lee Hoffer, a cultural and medical anthropologist at Case Western Reserve University who studies illegal drug use and substance abuse. “People want to do big surveys, but these are riddled with challenges.”

Hoffer’s work has helped expand the conventional understanding of local illegal drug markets from sellers and buyers to include middlemen, or “brokers.” Brokers are almost always users who buy drugs from dealers for their friends or other users and often get a cut of the heroin in exchange, which allows them to sustain their own habits.

“These are people that are essentially helping their peers. They don’t consider themselves dealers and no one else would, except the police,” Hoffer said. “Then it gets complicated. Who is the dealer, and how do you distinguish this person from other people?”

These complexities make it difficult to simply target one actor — the dealer or user — with tough enforcement or penalties. “Unless you understand the nuance of who’s a drug dealer on the continuum of using and selling, then law enforcement is always going to miss the mark,” said Jon Zibbell, a senior public health analyst at the nonprofit research institute RTI International.

Adding fentanyl to the mix when considering harsher drug penalties — as the Trump administration apparently wants to do — makes things even messier, and it’s another example of how the real world is often much more complicated than policies imagine. In many cases, users and sellers are unaware that fentanyl is present in other illicit substances they purchase. In an analysis by the U.S. Sentencing Commission, only 15 percent of those sentenced for trafficking fentanyl in 2016 in the U.S. were reported as clearly knowing they were selling fentanyl. Researchers also told me that they aren’t sure how prosecutors could begin to consider sentencing guidelines for fentanyl because dozens of variations of the drug exist on the street with different levels of potency.

Another recent study from the Johns Hopkins Bloomberg School of Public Health on fentanyl testing strips and other drug-checking technology found that users are concerned about and often unaware of the presence of fentanyl in drugs they have used. Of 256 respondents surveyed for the study who believed they had consumed fentanyl, only 26 percent said it was their drug of preference.

Zibbell recently wrapped up research for RTI on fentanyl test strips with the help of Vincent’s organization, and a paper will soon be submitted for review. During the study, Vincent noticed that people selling drugs were also among those using the testing strips.

“People who used drugs didn’t want fentanyl and they weren’t trying to buy it, and people who were selling drugs sure didn’t want the people that they’re selling the drugs to to die,” Vincent said.

Ramping up penalties is unlikely to help those people, and it could hurt them.

These policies are “going to be falling on these lower-level people,” said Eric Sevigny, a professor of criminal justice at Georgia State University. “They’ll be filling prisons and jails with those who probably need treatment, these user addicts who are often also selling to support their addiction. If you ramp up enforcement, that’s more likely the person to get caught up on the criminal justice side.”