Francisco Cantú never thought he would become a US Border Patrol agent.

The grandson of a Mexican immigrant, Cantú had been studying international relations in college, but became “tired of reading about the border in books” and wanted to see the realities of border life for himself. So in 2008, he went to Arizona to enlist in the US Customs and Border Protection Border Patrol Academy.

During his four years as a Border Patrol agent, Cantú sent men, women, and children trying to cross the American border back to Mexico. He spoke with people whose loved ones had been injured or killed during the treacherous journey, saw the desperation of those who sought work and a better life, and witnessed young girls being stopped from entering the US to reunite with their mothers.

As the years went on, he was tormented by nightmares. “A huge part is conditioning you to accept all these violent or traumatic things that can be part of the job, and to see that as part of your day-to-day work,” Cantú said.

In The Line Becomes a River, Cantú shares his experience working for four years as a Border Patrol agent, exploring how immigration statistics “[do] little to account for all the ways that violence rips and ripples through a society, through the lives and minds of its inhabitants.”

But over the past week, Cantú has come under fire as he promotes the book’s publication. Some critics argue that his book humanizes Border Patrol agents, and activists in San Francisco have called for his book reading to be canceled. An NPR headline — the “Border Patrol Does Good Work” — was “particularly damaging,” Cantú said in a statement. Instead, he said his primary aim in writing the book was to illustrate “the dehumanization of migrants.”

This conversation has been lightly edited for length and clarity.

Hope Reese

You became a Border Patrol agent because you had studied the border and wanted to see what it was like firsthand, but what about your co-workers? What draws people to this kind of work?

Francisco Cantú

I wasn’t a law enforcement-type person, so expected to be the odd man out. But I was surprised. Nearly a third to a half of the Border Patrol is Hispanic. A huge number come from the Southwest. Their parents were migrants. I’ve heard of agents who crossed over as kids and are first generation themselves. So all of those stereotypes — of, for instance, a white racist who wants to keep Mexicans out of the country — were turned on their head.

There are 18,000 agents — there are more Border Patrol than FBI, DEA — when you talk about that many people, there are people who are cruel and callous, and there are also some of the most kind and compassionate people I’ve ever met. For many, it’s a way out. For some, you either join the cartel or join the Border Patrol agency. People growing up in small communities near the border would see that the people who were the most well-off were either working for the cartel or working for the Border Patrol. It’s a generalization, but that’s something I heard.

Hope Reese

You write of being in Border Patrol: “It’s true that we slash their bottles and drain their water into the dry earth, that we dump their backpacks and pile their food and clothes to be crushed and pissed on and stepped over, strewn across the desert and set ablaze.” And recently, Border Patrol agents were accused of destroying water stations that had been installed by a humanitarian group. Is this behavior typical?

Francisco Cantú

It’s important to me to know that I never did that. But I saw it happen. I knew it happened. I wore a uniform, and I tried to grapple with this — my own culpability, and the ways I could and couldn’t extract myself from the institution I worked for.

One of the most impactful experiences was when I encountered a dead body in the desert. For me, to see the dead body and be the one talking to that person’s family in person when they’re in the middle of grappling with that death — I carry that with me all the time. Our policy of prevention through deterrence — pushing those crossing out from the heavily patrolled urban areas to the remote areas of the desert — serves to weaponize the landscape. That’s why people are dying in the desert.

The humanitarians that set up those water stations are working to fill a deadly void that has been left open in our policy. So for Border Patrol to destroy the aid they leave is unacceptable.

Hope Reese

You grappled with the question of what it means to be a “good” agent. How do you think about that now?

Francisco Cantú

There were parts of my nature that made me a good agent. I liked to be outdoors, to learn to read the landscape. And there was something exciting about the detective elements of the work — learning to cut for signs, track people through the desert, investigate smuggling cases.

But for me, there was always tension knowing that all these people I was positioned against were risking everything for a better life. You reach a point where you think: If I was a parent separated from my child, I would do the same.

There was a middle-aged woman who had become lost, and I was responsible for taking her back to the station. She had these silver dollar-sized blisters on her feet. I had also become licensed as an EMT, and I bandaged her feet. She watched me and thanked me. She called me a humanitarian. It was a strange moment. I’m not a humanitarian. I’m part of a system that is sending you back to a place from where you are risking your life to flee.

Hope Reese

How is the Border Patrol different or similar from the police or the military?

Francisco Cantú

Border Patrol is paramilitary — it’s between these two worlds. A huge part is conditioning you to accept all these violent or traumatic things that can be part of the job, and to see that as part of your day-to-day work. There isn’t a culture of talking about the ways you might be impacted by the trauma — that creeping unease about how a job can cause you to bottle up compassion or internalize violence.

Hope Reese

How critical are you of the Border Patrol as an institution?

Francisco Cantú

It’s important to remember that in the summer, the entire Border Patrol becomes a search-and-rescue mission. The realization that people are dying in the desert … Border Patrol agents on the ground aren’t writing border policy. But we’re enforcing it. The Border Patrol is simultaneously there to put out the fire, and the institution is what started the fire.

That’s what’s missing from our conversation about immigration reform. We still don’t acknowledge these people who are dying in our debate.

Hope Reese

You write about how it’s more difficult to attempt to cross the border than it was 20 years ago. What are the side effects of that “success”?

Francisco Cantú

Human smugglers are going to charge more, so it becomes more and more expensive for the people who are trying to cross. It also becomes more and more lucrative for the smugglers. The immigrant really becomes more and more of a commodity — it’s just another part of the spiral toward dehumanization.

Another part of what’s happened is that the drug cartels, as they have become more powerful, have taken control of the human smuggling operations.

Hope Reese

You observe that the language we use to describe migrants can be dehumanizing. Can you elaborate?

Francisco Cantú

We talk about immigration as a “flood.” A “wave” of migrants. In Spanish smugglers are called “polleros,” which means “chicken rancher.” And the migrants are chickens. What all of those metaphors do is lump the migrants into this indistinguishable mountain of people.

Hope Reese

After you left the Border Patrol, you worked at a coffee shop, and a man named José would come there to eat breakfast with you, every day, for two years. Then he left the US, his home of 30 years, and traveled to Mexico to visit his dying mother. When José attempted to return home to his wife and sons in the United States, he was arrested at the border and deported.

Francisco Cantú

José’s story transformed the way I see all of this. It gave me a deeper and more devastating understanding of the way the border rips through a person’s life. Not just the person who’s crossing, but the lives of their family.

For someone in José’s situation, if he’s on the other side trying to get back to his family, he’s terrified walking around in a border town because he’ll be preyed on by human smugglers. Human trafficking and drug trafficking in these communities are closely tied.

José’s family was literally extorted for money, and his life was threatened. He was afraid. And that happens to a lot of crossers. Or he will try to cross and be kidnapped by someone who will hold him for ransom. If he does make it, he’ll be terrified of getting pulled over on his way to work. I talked to some people who were afraid a helicopter would land on their yard and kidnap them in the middle of the night. It makes these people live a life in fear.

Hope Reese

What were your thoughts when you first heard Trump’s proposal of a wall?

Francisco Cantú

People don’t understand that there are already border walls, and 700 miles of fencing. At the station where I worked, there were several miles of 20-foot-high fencing, made up of these huge panels of steel mesh, and it really didn’t stop much. Smugglers would pry open panels from the ground, put these hydraulic tire jacks underneath, and lift them up so cars could drive underneath. Other smugglers would bring welding torches and weld doors or areas to crawl through.

In my experience, that’s not an argument for a bigger, stronger wall. No matter what obstacle we put up, people will find a way around it. So do we spend more time and money on a wall? Do we ask our policymakers to conceive of new ways to make our border more hellacious to cross? Or do we find ways to reform our system? Or send aid to these countries? There could be much better uses for that money.

Hope Reese

Was there a moment when you realized you wanted to leave the Border Patrol?

Francisco Cantú

At the time, I wouldn’t have told you I was leaving the Border Patrol because of all these nightmares, or because I had come to disagree with the work. I got a Fulbright fellowship to the Netherlands to study rejected asylum seekers who were remaining after their deportation orders. Pursuing studies was a way to get out that looked like I was moving forward. It wasn’t until I had distance that I began to grapple with what the dreams meant.

A few months before I left the Border Patrol, I went to see a movie about a guy who slowly lost the ability to tell the difference between his dreaming life and waking life. I remember driving home and breaking down, pulling over to the side of the road and weeping. I had to look at myself and realize — something’s happening here, you’re not all right.

Hope Reese

You have received some backlash in the last couple of days, with critics saying that your book humanizes Border Patrol agents and activists in San Francisco even calling for your book reading to be canceled. How do you respond?

Francisco Cantú*

In some of the interviews I gave, I’ve been asked, “Oh, the Border Patrol rescues people a lot, right?” Which is kind of a leading question. And I’ve said, “Sure, the Border Patrol rescues people.” But the larger picture is the violence of this policy of enforcement through deterrence is what is putting people there in the first place. It’s like the fire chief setting a fire and the firefighters getting praised for putting it out. One quote I gave in an interview was pulled out of context. I said “the border patrol does good work.” But I want to be clear: That’s not my message.

On a larger level, what I’ve seen unfold, even in this short week, is that there’s an eagerness among some media to humanize the Border Patrol. Since I represent a relatable Border Patrol agent, a lot of the media about the book has been focused on that, and given more weight to humanizing me as a former Border Patrol agent, or Border Patrol agents in general, over focusing on my message: the dehumanization of migrants.

The Border Patrol is backed by the most powerful country in the world. They wear the uniform of the US government. The migrants are the ones we need to be talking about and humanizing. They’re the ones whose identities and names are being overlooked. Migrants are constantly made anonymous by border policies.

*After answering this question from Hope Reese, Penguin Random House also provided Cantú’s statement to the news site Splinter.

Correction: The term “chicken rancher” used to describe smugglers is “pollero” in Spanish.

Hope Reese is a journalist in Louisville, Kentucky. Her writing has appeared in the Atlantic, the Boston Globe, the Chicago Tribune, Playboy, Vox, and other publications. Find her on Twitter @hope_reese.