The use of military forces to perform domestic functions — such as constructing barriers along the US-Mexico border — could pose fundamental legal, policy and administrative challenges.
“Military forces operating freely within civilian jurisdictions risk upsetting the constitutional balance between civil authority, the military, and the private sector,” the Army said this week in a newly updated manual.
Therefore, “Army leaders must ensure that even in a catastrophic event, Army support remains within the boundaries of constitutional principles, U.S. laws, DOD policies, and Army regulations,” the manual said. See Defense Support of Civil Authorities, Army Doctrine Publication 3-28, February 11, 2019.
As a practical matter, the Army publication said, “Commanders should begin by viewing each domestic operational environment as an assortment of civil authorities, each with primacy in its jurisdiction.”
When it comes to the possible use of military forces for construction on the US-Mexico border, there is in fact a multiplicity of government and private authorities that have primacy over different parts of the border.
A briefing slide prepared by the Congressional Research Service last week identified no fewer than six federal agencies with jurisdiction over portions of the border: Bureau of Land Management, Bureau of Reclamation, Department of Defense, Fish and Wildlife Service, Forest Service, and National Park Service. Still other portions of the border are under tribal authority or are privately held. See Background: Using Defense Funds for Construction in a National Emergency, CRS briefing slides, February 6, 2019 (at p. CRS-4).
Use of the military to construct barriers along the border would normally require coordination and cooperation with each of the affected parties. But if the President were to declare a national emergency, such requirements could potentially be set aside, placing the “constitutional balance” at risk.
“Even in a worst-case national emergency, the military will always operate under civilian control,” the new Army publication said.