Americans have a long-standing aversion to the use of the military in domestic affairs, one that antedates the founding of our republic. Concern about mistreatment by British soldiers was an animating force behind the American Revolution, and fears about the potential misuse of military power led the framers of the Constitution to, among other things, mandate civilian control of the armed forces, empower Congress to regulate the military, allow citizens to keep and bear arms and form citizen militias to quell uprisings, and place strict limits on when soldiers may be housed in citizens’ homes. During the first several decades of U.S. history, soldiers infrequently became involved in domestic matters; when they did, they were subordinate to the civilian authorities who had called for their assistance. This changed in the 1850s when Attorney General Caleb Cushing ruled that federal troops under command of their officers could be used to assist federal marshals enforcing the Fugitive Slave Act of 1850.
The practice of using troops to enforce domestic law continued for the next two decades. Union soldiers served to keep the peace in the southern areas they occupied during the Civil War, and federal troops did the same during the Reconstruction Era as the national government averred that military power was needed to maintain order in the face of Southern hostility against the changes wrought by the Civil War. During Reconstruction, federal troops regularly took law enforcement action to keep the peace, prompting concerns regarding the legitimacy of using soldiers as a police force. These concerns became heightened in the wake of the exceptionally close 1876 presidential election (determined by a single vote in the electoral college), as President Ulysses Grant had sent troops to help federal marshals police the polls in several Southern states. Worried about the encroachment of the military in the critical democratic endeavor of electing civilian leaders, Congress soon took action to limit the capacity of the military to enforce civil law.
In 1878, Congress passed an appropriations bill that included a section forbidding Army troops from taking law enforcement action absent constitutional or statutory authorization. Section 15 of Chapter 263 of the appropriations bill read:
From and after the passage of this act it shall not be lawful to employ any part of the Army of the United States, as a posse comitatus, or otherwise, for the purpose of executing the laws, except in such cases and under such circumstances as such employment of said force may be expressly authorized by the Constitution or by act of Congress; and no money appropriated by this act shall be used to pay any of the expenses incurred in the employment of any troops in violation of this section, and any person willfully violating the provisions of this section shall be deemed guilty of a misdemeanor and on conviction thereof shall be punished by fine not exceeding ten thousand dollars or imprisonment not exceeding two years or by both such fine and imprisonment.
Posse comitatus is a Latin term meaning ”the power of the county,” which refers to the capacity of a sheriff to enforce the criminal law within his or her county.
One of the powers sheriffs’ posses is to authorize others to assist them in carrying out their duties. Those assisting a sheriff are acting as a ”posse comitatus” (or just plain ”posse,” as in many movies about the Old West). Thus, the Army Appropriations Act of 1878 severely circumscribed both the power of local law enforcement authorities to call on members of the Army for assistance (that is, for soldiers to be employed as a posse comitatus) and for soldiers to otherwise take law enforcement action (that is, to otherwise execute the law). Given the prominent placing of the term posse comitatus in the section of the bill limiting the use of the military to enforce civilian law, the provision is commonly referred to as the ”Posse Comi-tatus Act” (PCA).
In 1956, Congress amended the PCA to streamline its language and bring the Air Force (which came into being after World War II) into its statutory purview. The PCA took its current form in 1994, when Congress once again amended it. Section 1385 of Title 18 of the United States Code presently reads:
Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act of Congress, willfully uses any part of the Army or the Air Force as a posse comitatus or otherwise to execute the laws shall be fined under this title or imprisoned not more than two years, or both.
While the PCA mentions only the Army and the Air Force, in 1986, the Department of Defense issued regulations extending its provisions to the Navy and Marine Corps. Thus, the PCA effectively restricts the capacity of all branches of the U.S. armed forces to take law enforcement action to situations clearly authorized by the Constitution or federal statute.
This is not to say, however, that the U.S. military is universally forbidden to enforce domestic law. Among the notable exceptions to the restrictions set out in the PCA are that it applies to neither the Coast Guard nor the National Guard. The
Coast Guard is excepted because during peacetime it falls under the authority of the Department of Transportation. The National Guard is not covered because guard units are state entities that operate under the authority of their governor (as per Title 32 of the U.S. Code), unless they are federalized by presidential authority (and then fall under Title 10 of the U.S. Code, which regulates the armed forces).
Another notable exception to the PCA is found in Chapter 15 of Title 10 of the U.S. Code, the so-called Insurrection Act. In short, the Insurrection Act permits the president to dispatch federal troops to enforce civil law on the request of state legislators or governors and when it is apparent that state authorities are either incapable of or unwilling to enforce federal law. This exception to the PCA was most recently used when California Governor Pete Wilson requested and received the assistance of federal troops during the 1992 Los Angeles riots. More recently, some commentators have asserted that the Insurrection Act should have likewise been invoked so that federal troops could help reestablish order in New Orleans in 2005, following Hurricane Katrina.
It is important to note that the PCA in no way proscribes the use of the military to carry out non-law enforcement activities on U.S. soil. Thus can the president, with no fear of running afoul of the PCA, order military units to assist local and state authorities in a variety of ways that bear no relation to enforcing the law when circumstances conspire to overwhelm them. In the wake of natural disasters or other sorts of crises, the military can deliver supplies, search for missing people, rescue stranded individuals, provide medical services, or supply any similar sort of assistance. While local, state, and federal civilian authorities can usually manage things following disasters, soldiers have occasionally been called on to help out, such as in San Francisco following the 1906 earthquake and in South Florida after Hurricane Hugo struck in 1992.
The notion that members of the military can assist civilian authorities as long as they do not enforce the law also applies to assisting police agencies in nonemergency situations. Soldiers can train local, state, and federal police officers; they can provide equipment and supplies to them; and they can offer technical assistance and do anything else that does not have them engaged directly in taking enforcement action. In recent decades, the military has been used to support a variety of law enforcement endeavors, most notably drug interdiction and policing our southern border.
That the military can, and does, legally work so closely with law enforcement agencies is a contentious topic. Some argue the status quo is sound, as military support is necessary for effective law enforcement; military assets are needed to effectively interdict drugs, for example. Others argue that allowing the military to so closely support the police is an invitation to disaster and the loss of the precious liberties the PCA is intended to protect. Those opposed to the close working relationship between the military and civilian law enforcement point to cases where the presence of the military has led to bad outcomes—the 1997 shooting death of a young man near the Mexican border by a Marine patrol that was helping out with immigration enforcement, for example— as evidence that it is not a good idea.
The controversy about the appropriateness of using the military to support law enforcement activities indicates that the long-standing American concern about military power is alive and well in the twenty-first century. The PCA—in its various manifestations—has played a central role in demonstrating this concern for the past century and a quarter even though no person has been prosecuted for violating it. As the new century unfolds and new law enforcement challenges arise in a post-September 11 world, the use of the military in American police work will continue to be a contentious topic. And, whether it retains its current form or is in some way altered, the Posse Comitatus Act will continue to play a crucial role in delimiting the bounds within which the military may be legally used in domestic law enforcement.
