Strengthening Military Border Mission
by C. Todd Lopez, DOD News
April 21, 2025

On April 11, 2025, a national security presidential memorandum directed the Defense Department to accept jurisdiction of certain federal lands along the southern border from other agencies.

"Our southern border is under attack from a variety of threats," President Donald J. Trump said in the memorandum. "The complexity of the current situation requires that our military take a more direct role in securing our southern border than in the recent past."

The change directed in the president's memorandum will enhance the ability of service members to conduct their mission at the border.

The Defense Department, Interior Department and Department of Homeland Security already use land along the southern border. Included in that is the Roosevelt Reservation, a 60-foot strip of land lying parallel to the international boundary between the United States and Mexico. The memorandum notes that "Federal Indian reservations" are excluded.

It directs DOI and DHS to cede jurisdiction for portions of their land to DOD. That noncontiguous land, about 170 square miles, runs along the border between New Mexico and Mexico.

Once the Army accepts jurisdiction of that land, it will become part of a national defense area — a specified piece of federal land over which DOD maintains administrative authority and jurisdiction and is permitted to establish and enforce a controlled perimeter and access.

The area will be considered an extension of Fort Huachuca, Arizona.

Service members stationed at the border and operating on that land will have greater authority to execute their mission. They will be governed by the same rules as when they are defending any other military installation, such as apprehending trespassers and passing them to appropriate civilian or federal law enforcement officials.

Under the new arrangement, military personnel will continue to work together with U.S. Customs and Border Protection personnel to establish and enforce a controlled perimeter and controlled access to the area as part of an effort to repel unlawful mass migration, narcotics trafficking, migrant smuggling, human trafficking and other cross-border criminal activities.

To deter unlawful entry, service members will construct and position temporary barriers, detect and monitor the use of routes across or adjacent to the area and apprehend individuals who breach the barriers. Service members will place signs and construct temporary barriers to visibly indicate the boundaries.

Military operations at the southern border fall under the jurisdiction of U.S. Northern Command, which remains ready to adjust its operations in response to the memorandum.

"U.S. Northern Command continues to plan and prepare to serve as the operational lead for the implementation of the national defense area," said Marine Corps Col. Kelly Frushour, Northcom director of public affairs. "Forces responsible for securing the national defense area will conduct any necessary training to perform their assigned tasks effectively."

U.S. Department of Defense

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