Posse Comitatus Act (1878)

1) Link to the Text of the Act
Read the statute (18 U.S.C. § 1385)

2) Why It Was Done
Enacted after Reconstruction to limit the use of the U.S. Army in domestic law enforcement. It reinforced the separation between military and civilian authority.

3) Pre-existing Law or Constitutional Rights
The Constitution already divides civil and military powers, but before this law, federal troops were frequently used to enforce laws and support Reconstruction governments. This Act codified stricter limits.

4) Overreach or Proper Role?
Generally viewed as a necessary safeguard for civilian governance. Some argue exceptions (like the Insurrection Act) undermine its force.

5) Who or What It Controls

• Federal military forces (Army, Air Force, extended by DoD to Navy and Marine Corps, and by policy to Space Force)
• Federal executive branch when considering military use in civilian law enforcement

6) Key Sections / Citations

• 18 U.S.C. § 1385

7) Recent Changes or Live Controversies

• Raised in debates whenever federal troops are considered for domestic protest or border operations
• Exceptions and interpretations continue to spark political/legal disputes

8) Official Sources

• U.S. Code – Title 18, § 1385
• DoD Law of War Manual – PCA Section

• Military
• Domestic Law Enforcement
• Civil-Military Relations
• Federalism