What Is the Posse Comitatus Act?

Recently President Bush asked Congress to consider allowing the military to assume police functions in the event of national emergencies. In the media there have been references to a posse comitatus law that currently prevents this.

What in the world does “Posse Comitatus” mean? How does it affect ordinary citizens?

Posse comitatus is Latin for “power of the county.” The term refers to a sheriff’s common-law authority to arrange citizens into a posse in order to enforce laws. It appeared in English law in the 1400s after a riot that took place.

While in England posse comitatus referred to the grant of police powers to civilians, in America, posse comitatus refers to the military enforcement of civilian laws. Americans, from the beginning, have been leery of laws being enforced by the military.

This prejudice against the military is rooted in our experience during Colonial times. In the tumultuous years preceding the American Revolution the British military was sent to the colonies to enforce British control. In the Declaration of Independence, Jefferson expressly cited the use of the British military in America as one of the colonists' central grievances: “He [the king] has kept among us, in times of peace, standing militaries without the consent of our legislatures. He has affected to render the military independent of and superior to the civil power."

Once the United States was formed, Americans were determined to protect themselves from an overbearing military. The Articles of Confederation limited the role of the military. The Constitution mandated civilian control of the military, with the elected president serving as commander-in-chief.

Prior to the Posse Comitatus Act, or PCA, soldiers who took on a policing role were usually average citizens, not professional soldiers. Civilian rights were protected by the so-called Mansfield Doctrine, which gave citizens the right to sue or criminally prosecute those who abused their power as members of a posse.

During the Civil War civilian rights were eroded. President Lincoln even suspended the writ of habeas corpus. A habeas corpus petition forces the courts to produce a prisoner (the body of the person) so it can be determined if that person is being lawfully held. In voiding this right Lincoln made it clear that jailed sympathizers of the Confederacy could not use the writ of habeas corpus to compel their release from prison. Congress approved Lincoln's suspension of habeas corpus (after the fact) and barred the Supreme Court from challenging the suspension of the writ. This was done in an effort to keep Confederate rebels from using the Constitution against the Union.

After the Civil War in the period known as Reconstruction federal laws were enacted further restricting the rights of the now defeated rebels. The military was sent to the Southern states in order to perform policing duties. In the election of 1876 -- the infamous contested election between Democrat Samuel Tilden and Republican Rutherford B. Hayes -- U.S. soldiers were ordered to protect the rights of black freedmen during the election. Southern Democrats claimed that in three states they truly won the military blocked their voters from voting--or scared them into voting for Hayes. Republicans said that the military merely helped black people cast ballots without intimidation. In a deal ending the controversy, Democrats agreed to concede victory to Hayes in return for the withdrawal of the military from the Southern states, among other demands. Republicans agreed.

The Posse Comitatus Act was passed in the wake of the controversial election. It was pressed by Democrats eager to ensure that in the next election the military would not be used to help black freedmen vote. The act states, “Whoever, except in cases and under such circumstances expressly authorized by the Constitution or by an Act of Congress, willfully uses any part of the Army as a posse comitatus or otherwise to execute laws shall be fined no more that $10,000 or be imprisoned not more than two years, or both.” The act was passed in 1878.