The U.S. southern border at the nexus of Texas, New Mexico and Cuidad Juarez, Mexico. (Anna Watts/The Washington Post)
The Trump administration is evaluating plans for the Pentagon to take control of a buffer zone along a sprawling stretch of the southern border and empower active-duty U.S. troops to temporarily hold migrants who cross into the United States illegally, according to five U.S. officials familiar with the deliberations.
Those discussions have been underway for weeks, and they center, in part, on a section of border in New Mexico, officials said, speaking on the condition of anonymity to disclose details of the plan. In effect, the move would turn the buffer zone into an expansive satellite military installation, potentially allowing a greater portion of the Defense Department’s mammoth budget to pay for President Donald Trump’s border crackdown while creating new legal jeopardy for those caught trying to slip into the country from Mexico, these people said.
Any move to militarize the southern border’s buffer zone is certain to raise questions about whether employing the military in this way runs afoul of the Posse Comitatus Act, a federal law that prohibits active-duty troops from most law enforcement missions. The Trump administration has addressed such legal considerations by having Customs and Border Protection (CBP) or Immigrations and Customs Enforcement (ICE) detain people and move them once in custody, including on U.S. military flights involved in its deportation efforts.
If the plan is approved, and administration officials deem it successful, the military-controlled buffer zone, measuring 60 feet deep, eventually could stretch west to California, officials said.
As part of the effort, senior Pentagon officials have asked military officers to examine whether any legal complications could arise from having U.S. troops temporarily hold illegal border crossers when CBP agents are not immediately available to arrest them, officials said. By militarizing the buffer zone, the theory goes, any migrant apprehensions made by service members would be tantamount to catching trespassers on a military base: The troops involved would simply hold them until law enforcement arrives.
“It’s very, very careful on that wording,” said one defense official familiar with the discussion. “It’s not ‘detention’ because once you go into detention it has the connotations of being detained for arrest. This is holding for civilian law enforcement.”
The White House has been involved in the discussion for some time, said a senior administration official and a second defense official. The senior administration official said it is not yet clear if Trump will approve the plan but that officials see value in establishing a national defense zone at the border that could come with enhanced penalties for migrants crossing illegally, including accelerated deportation.
Spokespeople for the Pentagon, Department of Homeland Security and the White House National Security Council did not respond to several requests for comment.
Since returning to office, Trump has doubled down on his aggressive approach to immigration enforcement, ramping up arrests and deportations and in some cases clashing with federal judges evaluating the constitutionality of his directives.
He has ordered active-duty troops and an increasingly broad array of weapons and technology to the southern border, and on Saturday, officials dispatched a Navy destroyer, the USS Gravely, to join the mission at sea. Trump also has sought to expand use of military facilities, including the infamous detention camp at Guantánamo Bay, Cuba, for holding undocumented immigrants facing deportation.
As of Monday, more than 10,000 active-duty service members are involved in border security efforts, U.S. military officials said in a statement. At the same time, illegal crossings documented by CBP have plummeted, from 124,522 in December under President Joe Biden to 28,654 in February.
Trump administration officials have said they want 100 percent control of America’s borders and to stop the flow of illegal drugs into the United States.
The plan under consideration involves a 60-foot-wide strip of the southern U.S. border that lies within the Roosevelt Reservation, federal land that President Theodore Roosevelt set aside for border security in 1907. It extends from New Mexico to California. Typically, the land is controlled by the Interior Department, though jurisdiction for parts of it have been temporarily transferred to the Pentagon in the past, including during the first Trump administration, to facilitate border wall construction.
U.S. law allows the federal government to transfer up to 5,000 acres at a time to the Defense Department without congressional approval. The full length of New Mexico’s southern border is about 180 miles. It was not immediately clear if the administration intends to militarize all of it.
In recent days, the Defense Department has expanded its presence along the southern border, establishing a new joint task force with the 10th Mountain Division out of Fort Drum in New York overseeing the mission from a headquarters at Fort Huachuca in southeastern Arizona. If the buffer zone plan is approved, the strip of land would likely become a temporary annex of an existing military installation, probably Huachuca, officials said.
Among the most significant deployments approved thus far is the roughly 2,400 soldiers from the Army’s 4th Infantry Division, 2nd Stryker Brigade Combat Team, from Fort Carson in Colorado. Soldiers from the unit are now at Fort Huachuca and Fort Bliss, an Army installation in El Paso, near the New Mexico border, according to defense officials and photos released by the Pentagon.
As first reported by The Washington Post this month, their deployment is expected to include 20-ton armored Stryker combat vehicles. Pentagon officials have scrutinized several related issues in recent weeks, including whether the Strykers can maneuver effectively in the 60-foot strip of buffer zone, and if they can drive on nearby roads without damaging them, defense officials said.
It remains unclear when or how the Strykers will be used. While they can carry up to 11 soldiers at a time and possess long-range sensors and optics that defense officials consider useful in detection efforts, similar technology exists that could be deployed more affordably, defense officials said.
Marianne LeVine contributed to this report.
