Posse Comitatus Act

The Posse Comitatus Act restricts the circumstances under which U.S. military forces can be used to address domestic disturbances. Passed in 1878 in response to the South's anger at the use of federal troops during Reconstruction, it has since evolved into an important—if often misunderstood—foundation of American civil–military relations.

Posse comitatus—literally ”power of the county”—was a legal concept carried into the American tradition from English common law. It held that, when necessary, authorities could call forth the entire male citizenry to aid in the execution of the law (from which was derived the ”posses” of Western lore). During the postCivil War Reconstruction period, Republican state and local officials in the former Confederate states, facing violent opposition from elements of the heavily Democratic southern white population, resorted to the deputization of local U.S. Army troops under posse comitatus to enforce laws and apprehend suspects. This had been done primarily in cases involving organized intimidation or assaults on African Americans or white Republicans (ironically, the legal precedent for the use of the Army as a posse comitatus had been set during the 1850s through the use of soldiers to apprehend fugitive slaves). The Grant administration and the Republican controlled Congress supported this policy. Despite military assistance to southern Republican governments, southern Democrats gradually regained control over the former Confederate states during the 1870s, a process that culminated in the Compromise of 1877, which resolved the crisis resulting from the disputed 1876 presidential election. With Reconstruction officially concluded, southern Democratic congressmen pushed through the Posse Comitatus Act to ensure that the Army could not be used against them in the future. Disillusioned by years of service in the South, the Army leadership broadly supported the measure. The consequence was that employing the Army to enforce the law would in the future be specifically restricted:

Despite its rather sinister origins, by restricting the employment of the U.S. military in domestic conflicts, the [Page 645]act serves an important function. The Posse Comitatus Act does not forbid the use of troops in domestic law enforcement (a common misconception). Rather, it requires the president to issue a direct order authorizing their employment for such purposes.

Although presidents in the years since 1878 have often employed military forces to restore order—the most notable recent instance is the 1992 Los Angeles riots—the Posse Comitatus Act has generally ensured that decisions to employ military force are made by the president rather than by state or local officials or Army officers in the field. In so doing, the Posse Comitatus Act has generally acted to substantiate the desire of civilian and military leaders alike to limit the domestic employment of federal military forces.

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