Trump Unveils Plan to Militarize Southern Border, Expanding Defense Department’s Role

By Joseph & Hall PC | April 2025

In a bold escalation of border policy, President Trump announced on April 11, 2025, the launch of a new military initiative aimed at securing the U.S.-Mexico border. Framing the effort as a response to what he called ongoing “invasions,” the administration’s directive grants sweeping authority to the Department of Defense (DoD) over certain federal lands near the border.

The plan, detailed in a presidential memorandum, outlines the use of federal property—including the Roosevelt Reservation, a 60-foot-wide strip of federally controlled land that spans much of the southern border—for military purposes. The Department of Defense will gain jurisdiction over these lands for the purpose of installing border barriers, deploying surveillance and monitoring systems, and conducting other military operations deemed necessary to enforce border security.

Initially, the operation will focus on a “limited sector” of federal land selected by the Secretary of Defense. However, the memorandum authorizes the Secretary to expand the scope of the mission to additional areas at any time, in coordination with other federal agencies and departments.

The move marks a significant shift in border management strategy, blurring the line between civilian border enforcement and military operations. While past administrations have deployed National Guard units to assist with border security, this new policy formalizes a longer-term military role in managing and controlling the border.

Critics argue that the decision could provoke legal challenges over the militarization of domestic spaces and raise constitutional concerns regarding the use of the armed forces within U.S. borders. Supporters, meanwhile, view the policy as a decisive step toward regaining control over immigration and border enforcement.

As implementation begins, observers are watching closely to see how far the Defense Department will extend its reach—and how states, advocacy groups, and communities along the border will respond.