Why We Sought National Defense Zones Along the U.S. Southern Border

Our reporting started, like much of our work, in a spreadsheet. Analyzing federal court data, I noticed something strange: Within months of President Donald Trump’s inauguration in January 2025, prosecutors began filing obscure charges related to trespassing on military property — so many, in fact, that more cases were filed in 2025 than in the previous decade.

Nearly all of those accusations came from cases along the U.S. southern border, where last spring the White House designated large swathes of territory as national defense zones. Placing them under military authority allowed troops to play an unprecedented role in arresting undocumented immigrants; Federal soldiers are generally prohibited from enforcing the law on national territory. If you were arrested in one of these areas, the government could now prosecute you for violating federal laws, including one passed in 1909 to keep spies out of armories.

In a survey that we published Recently, my co-reporters Perla Trevizo, Abe Streep, Pratheek Rebala and I delved into what experts say is a major flaw in these prosecutions that threatens to entrap people for crimes they didn’t commit: The migrants didn’t know that the land they were crossing now belonged to the armed forces. And many judges have ruled that you can’t be guilty of trespassing on military land if you didn’t know you were there.

Since April of last year, we have seen that at least 4,700 immigrants already accused of entering the country illegally have been charged with military intrusion; at least one of them had to wait more than a month in prison to be tried. Most of the accusations did not hold up. In fact, we found that in 60% of resolved cases, trespassing charges were dropped or dismissed. Yet prosecutors continued to file them.

Download the full data used in our analysis on our GitHub page.

As we visited courtrooms in West Texas and New Mexico and reviewed the records, it became clear how difficult it would be to prove that someone knowingly trespassed on military land. Some didn’t know how to read. At least one person spoke neither English nor Spanish. The small signs are widely spaced and easy to miss, and many migrants have been stopped far from them.

A Justice Department spokesperson said the prosecutions deterred unauthorized border crossings and cartel activity. And prosecutors argued in court that the illegal crossing was enough to prove criminal intent for the military intrusion charges. Top officials in the U.S. attorney’s offices handling trespassing cases declined repeated interview requests.

In November, Perla, Abe and I undertook a reporting trip to southern New Mexico and west Texas to see for ourselves what information we could gather about where the areas were and how they were marked.

Abe and I arranged a ride with Doña Ana County Sheriff Kim Stewart, whose New Mexico agency shares jurisdiction with the Border Patrol and the Army in one of the areas. A sergeant from his office led us along a dirt road parallel to the border, pointing out 12-by-18-inch red and white signs in front of the fence. She told us that her office had not received specific information on the location of the military zone boundaries; all they had were the signs. Even in broad daylight, it was difficult to read the words on it unless you got within a few feet.

On another outing in New Mexico — this time with photographer Paul Ratje — I went to a spot in Sunland Park where Ratje said he had previously taken photos of the border fence. The 2-acre dirt lot was less than a mile from residential neighborhoods and a popular Italian restaurant. From the parking lot we could see more red and white signs along the nearby border road.

While we were taking photos, a van in Border Patrol colors approached us. I was surprised to see that inside, instead of Border Patrol agents, there were two Army soldiers. The soldier in the passenger seat showed us the signs along the border road and told us not to go that way. The border road was part of the defense zone, he told us, but not the terrain we were in.

The next day, Perla and I returned to the same place. This time, a Border Patrol agent arrived. The pitch was part of the defense zone, he explained to us. When I pointed out that I had received conflicting information the day before, the agent said that the military had told him that no one could be in that area. We left. (An Army spokesperson said the base responsible for the defense zone in New Mexico published a map in December; the lot was not included.)

My interactions with the Border Patrol and the military thus far had only added to our confusion about these areas. Later that day, Perla and I drove south to a stretch of border fence along the Rio Grande near Tornillo, Texas. We saw a Border Patrol van near a gate in the fence. We thought we’d try asking where the defense zone was. Before we could do that, another Border Patrol van pulled up to us. Soldiers, one of whom had a rifle on his shoulder, got out of the two vehicles. Another soldier told us he was “not at liberty to discuss” the exact location of the national defense zone.

The answer baffled us. We asked him how we were supposed to know if we were in violation. He shrugged his shoulders. (Spokespeople for U.S. Customs and Border Protection and the Department of Defense did not directly respond to questions about these interactions.)

As we got back into our rental SUV, Perla and I wondered: If we, as journalists who investigate the situation for a living, couldn’t get a clear answer about where these military zones were, how did the government expect people crossing the border to do better?

In the four months between our reporting trip and the publication of our investigation on March 16, the government continued to file charges of military intrusion in more than 1,300 cases. New military zones were also created in Arizona, California and Texas.