WASHINGTON — The Trump administration is moving to transfer control of a stretch of land along the U.S.-Mexico border to the Department of Defense, enabling the U.S. Army to operate the area as part of a military base — a shift that could allow troops to detain individuals, including migrants, according to U.S. officials familiar with the plan.
The land, part of the Roosevelt Reservation — a 60-foot-wide federal strip running along the border from New Mexico to California — has historically been managed by the Department of the Interior. However, a presidential directive issued Friday night mandates the land be reassigned to the Department of Defense, raising significant legal and operational questions.
The move represents the most extensive attempt yet by the Trump administration to leverage military resources for border enforcement, circumventing the Posse Comitatus Act, a longstanding federal law prohibiting active-duty military from engaging in domestic law enforcement activities.
Under the new arrangement, the Army would treat the land as an extension of an existing installation, effectively enabling military personnel to conduct enforcement actions against those who enter the area without authorization. Individuals detained by Army security forces — including migrants crossing the border illegally — would be handed over to local civilian law enforcement agencies, officials said.
A 45-day test period is planned for a section of the Roosevelt Reservation in New Mexico, located near Fort Huachuca, an Army base in Arizona. During this trial, additional fencing and no-trespassing signage will be installed. The intent, officials say, is to evaluate the feasibility of using Army-controlled land to secure the border.
Officials who spoke to the Associated Press on condition of anonymity said the Pentagon is still reviewing the legal and operational implications of the transfer. Despite the ongoing legal review, they confirmed that the administration’s goal is to enable direct military involvement in detaining migrants on the borderland now classified as a military base.
Legal experts warn that the plan is likely to face immediate court challenges. Elizabeth Goitein, a presidential powers expert at the Brennan Center for Justice, said the strategy stretches the limits of legal authority under the military purpose doctrine — a narrow exception to the Posse Comitatus Act allowing domestic military activity if it serves a clear military function.
“This doctrine only applies if law enforcement is incidental to the primary military purpose,” Goitein said. “If the land’s main function is to aid border enforcement, as this transfer clearly suggests, it is highly likely to be struck down in court.”
Until now, military roles at the border have been restricted to support operations — such as constructing barriers, providing logistical assistance, conducting surveillance, and facilitating deportation flights. Some deportation efforts have included transporting detainees to offshore facilities like Guantanamo Bay. Troops have also served as administrative support for U.S. Customs and Border Protection agents but have not carried out direct arrests.
The National Security Council did not respond to requests for comment on the administration’s intentions or the legal risks associated with the transfer.
It remains unclear whether the Army will deploy additional personnel to manage the newly controlled territory. Currently, about 7,100 active-duty service members under federal control are assigned to border support missions, alongside roughly 4,600 National Guard troops under state authority.
The Roosevelt Reservation was originally established in 1907 as a buffer zone to prevent cross-border smuggling and to maintain federal access for monitoring activities. However, the Trump administration’s decision to militarize the corridor could reshape the legal boundaries of military involvement in immigration enforcement.
Critics of the administration’s border policies view the latest development as part of a broader strategy to normalize military engagement in civilian immigration issues, a tactic that has previously drawn opposition from state and local leaders, as well as civil rights groups.
As the trial phase of the land transfer proceeds, legal observers and immigration advocates are preparing for what could become a landmark legal battle over the limits of presidential authority, military jurisdiction, and civil liberties on American soil.
