Military Mission for Sealing the Southern Border of the United States and Repelling Invasions

Memorandums

TLDR

This memorandum reframes border security as a military mission, authorizing the Defense Department to take jurisdiction over federal lands along the southern border for barrier construction and military operations. It invokes emergency powers to bypass normal land use limitations, establishes phased implementation starting with limited sectors, and creates a framework to militarize portions of the border under military rules of engagement, raising potential legal questions regarding the Posse Comitatus Act.

This National Security Presidential Memorandum (NSPM-4) directs the Secretaries of Defense, Interior, Agriculture, and Homeland Security to implement military operations to “seal” the southern border and “repel invasions.” It authorizes the Department of Defense to take jurisdiction over federal lands along the border (including the Roosevelt Reservation but excluding Federal Indian Reservations) for border barrier construction, surveillance equipment installation, and military activities. The memorandum invokes emergency powers allowing the Interior Secretary to withdraw public lands for Defense Department use without normal limitations.

Key provisions include:

  1. Designates border security as a “military mission” rather than law enforcement
  2. Authorizes transfer of federal land jurisdiction to the Department of Defense
  3. Permits the designation of federal border lands as “National Defense Areas”
  4. Invokes 43 U.S.C. 155 to bypass normal public land withdrawal limitations
  5. Establishes a phased implementation, starting with a limited sector of federal lands
  6. Requires the Defense Secretary to assess the initial phase within 45 days
  7. Preserves the Defense Secretary’s authority to authorize and request National Guard deployments

This memorandum represents a significant shift in border policy by:

  • Reframing migration as a military threat requiring armed forces response rather than law enforcement
  • Using presidential emergency powers to bypass normal land use limitations
  • Creating a legal framework to militarize large portions of the southern border
  • Potentially expanding military jurisdiction over civilian border regions
  • Establishing military rules of engagement for border operations

The memorandum relies on Executive Order 14167 and Proclamation 10886 (both dated January 20, 2025) which presumably declared a national emergency and authorized these expanded military powers. The constitutionality of using active-duty military forces for domestic law enforcement-adjacent activities raises significant legal questions under the Posse Comitatus Act, which generally prohibits military forces from acting as domestic law enforcement.

NATIONAL SECURITY PRESIDENTIAL MEMORANDUM/NSPM-4

MEMORANDUM FOR THE SECRETARY OF DEFENSE THE SECRETARY OF THE INTERIOR
THE SECRETARY OF AGRICULTURE
THE SECRETARY OF HOMELAND SECURITY

SUBJECT: Military Mission for Sealing the Southern Border of the United States and Repelling Invasions

As the Chief Executive and Commander in Chief, the United States Constitution empowers me to direct the various elements of the executive branch to protect our homeland and ensure the territorial integrity and sovereignty of the United States in the manner I deem most efficient and effective, consistent with applicable law. Our southern border is under attack from a variety of threats. 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. Through Executive Order 14167 of January 20, 2025 (Clarifying the Military’s Role in Protecting the Territorial Integrity of the United States), Iassigned the Armed Forces of the United States the military missions of repelling the invasion and sealing the United States southern border from unlawful entry to maintain the sovereignty, territorial integrity, and security of the United States. This memorandum provides additional guidance on securing the southern border to the heads of certain executive departments.

Section 1.

Policy.

(a) to accomplish the military missions described inExecutive Order 14167, and to ensure the safety and security of the military and other Federal personnel in areas of military operations within Federal lands along the southern border, the Secretary of Defense, the Secretary of the Interior, the Secretary of Agriculture, and the Secretary of Homeland Security shall take all appropriate actions:

(i) to provide for the use and jurisdiction by theDepartment of Defense over such Federal lands, including the Roosevelt Reservation and excluding Federal Indian Reservations, that are reasonably necessary to enable military activities directed in this memorandum, including border-barrier construction and emplacement of detection and monitoring equipment; and

(ii) to provide for transfer and acceptance of jurisdiction over such Federal lands in accordance with applicable law to enable military activities directed in this memorandum to occur on a military installation under the jurisdiction of the Department of Defense and for the designation of such Federal lands as National Defense Areas by the Secretary of Defense.

(b) The Secretary of the Interior shall allow the Secretary of Defense to use those portions of the Roosevelt Reservation not yet transferred or withdrawn under this memorandum. In accordance with Proclamation 10886 of January 20, 2025 (Declaring a National Emergency at the Southern Border of the United States), 43 U.S.C. 155 is hereby invoked and the Secretary of the Interior may make withdrawals, reservations, and restrictions of public lands to provide for the utilization of public lands by the Department of Defense to address the emergency at the southern border, without regard to any limitation on withdrawals otherwise applicable under the terms of the Engle Act, 43 U.S.C. 155-158.

© The Secretary of Defense may determine those military activities that are reasonably necessary and appropriate to accomplish the mission assigned in Executive Order 14167 and that are necessary to protect and maintain the security of military installations, consistent with section 2672 of title 10, United States Code, and the longstanding authority of amilitary installation commander to exclude persons from a military installation, as recognized in section 21 of the Internal Security Act of 1950 (50 U.S.C. 797) and 18 U.S.C. 1382.

(d) In carrying out activities under this memorandum, members of the Armed Forces will follow rules for the use of force prescribed by the Secretary of Defense.

Sec.2. Phased Implementation.The Secretary of Defense, the Secretary of the Interior, the Secretary of Agriculture, and the Secretary of Homeland Security will initially implement this memorandum on a limited sector of Federal lands designated by the Secretary of Defense. Within 45 days of the date of this memorandum, the Secretary of Defense shall assess this initial phase. At any time, the Secretary of Defense may extend activities under this memorandum to additional Federal lands along the southern border in coordination with the Secretary of Homeland Security, the Assistant to the President and Homeland Security Advisor, and other executive departments and agencies as appropriate.

Sec. 3.

General Provisions.

(a) Nothing in this memorandum shall be construed to impair or otherwise affect:

(i) the authority of the Secretary of Defense to authorize and request that State Governors order members of the National Guard under authority of title32 of the United States Code to conduct Department of Defense activities, including as appropriate to support law enforcement activities under the responsibility of the Attorney General or the Secretary of Homeland Security, if requested by such official;

(ii) the authority granted by law to an executive department or agency, or the head thereof; or

(iii) the functions of the Director of the Office of Management and Budget relating to budgetary, administrative, or legislative proposals.

(b) This memorandum shall be implemented consistent with applicable law and subject to the availability of appropriations.

© This memorandum is not intended to, and does not, create any right or benefit, substantive or procedural, enforceable at law or in equity by any party against the United States, its departments, agencies, or entities, its officers, employees, or agents, or any other person.

DONALD J. TRUMP