Trump's Deployment of National Guard Raises Questions About the Posse Comitatus Act

The U.S. military is prohibited from carrying out domestic law enforcement under the Posse Comitatus Act, a law passed in 1878 after the end of Reconstruction. President Donald Trump's recent deployments of National Guard troops to Washington, D.C. and Los Angeles have sparked concerns about the application of this law. According to Dan Urman, director of the law and public policy minor at Northeastern University, the National Guard is often caught between state and federal authority, with the guard generally reporting to state governors but being subject to federal authority when called into service.

Key Takeaways:

• The Posse Comitatus Act, passed in 1878, prohibits the U.S. military from carrying out domestic law enforcement.
• President Trump's deployment of National Guard troops to Washington, D.C. and Los Angeles has raised questions about the application of this law.
• According to Dan Urman, director of the law and public policy minor at Northeastern University, the National Guard is often caught between state and federal authority.
• The law prohibits the military from investigating local crimes and allows only for federal law enforcement or suppressing rebellions with express authorization from the Constitution or Congress.
• A recent deployment of National Guard troops to Los Angeles was ruled by a federal district court judge to have violated the Posse Comitatus Act.
• A White House spokesperson has stated that President Trump is "well within his lawful authority" to deploy the National Guard in Washington, D.C. to protect federal assets and assist law enforcement.

Statistics:

• The Posse Comitatus Act was passed in 1878 (Source: Tanner Stening, September 9, 2025).
• The National Guard is generally subject to state governors but subject to federal authority when called into service (Source: Dan Urman, Northeastern University).
• President Trump dispatched 2,000 National Guardsmen to California to protect Immigration and Customs Enforcement agents in June (Source: Tanner Stening, September 9, 2025).
• Local crime statistics show that violent crime in Washington, D.C. was down about 23% from August 12-26 compared to the previous two weeks (Source: Tanner Stening, September 9, 2025).
• More than 2,000 National Guard members from D.C. and other states were deployed to Washington, D.C. to crack down on crime in response to President Trump's executive order (Source: Tanner Stening, September 9, 2025).
• Federal officials reportedly made over 1,000 arrests during the National Guard's deployment in Washington, D.C. (Source: Tanner Stening, September 9, 2025).

Sources:

• Tanner Stening, September 9, 2025
• Dan Urman, director of the law and public policy minor at Northeastern University