What is the Posse Comitatus Act?

The Posse Comitatus Act, which was enacted in 1878 and codified as 18 U.S.C. § 1385, states:

“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.”

The Posse Comitatus Act disallows the use of federal troops as a police force unless Congress overrides it, or the use of force is “expressly authorized by the Constitution.” However, the Constitution does not provide for military use as a police force in any capacity, so this phrase has been one that the courts have not been able to answer.

Congress has, however, authorized the use of the Army in some situations as shown in U.S. Codes Sections 251-255 and 271-284. Although, those codes ensure that the military is not used directly as a police force. However, there are some caveats to this. First, the Coast Guard has, by act of Congress, been designated as having law enforcement responsibilities. Second, during the Wounded Knee occupation in 1973, the military was given specific and limited powers for the military to assist the police.

It should also be noted that the only branches of the military that are covered by the Posse Comitatus Act are the Army, and through later inclusion, the Air Force. The Navy and the Marine Corps are restricted by other legislation that appears in the Department of Defense Instruction. The Coast Guard is used as a police force unless it is called into war when it is placed within the Navy, and thus restricted by the Department of Defense. The National Guard is unique, in that it is both connected with federal and state law. While this can be a matter of interpretation, if the federal government makes a directive to the National Guard, it is blocked from the use as a police force because then it comes under the Department of Defense Instruction.

Why is it important to discuss today?

In recent years President Trump has called for the use of federal troops for domestic purposes on two occasions. First, he asked for troops to police the Southern border. Second, he mentioned using troops as a force to end rioting connected to protests over systemic racism.

This act, however, has had an impact before President Trump. In 2009, after Michael McLendon killed 10 people at Fort Rucker, a number of troops were used in a police function. While President Obama did not authorize their use, nor did the governor of Alabama, those who were part of this action received “administrative” punishment for violating the Posse Comitatus Act.

President George W. Bush asked Congress to amend the law so that the military could be used to assist in natural disaster relief after Hurricane Katrina.

Why was it passed?

As troop numbers increased beyond any point in American history during the years of the Civil War, the nation had to grapple with the question of a large standing Army and how it perceived such an Army as a potential threat to democracy. While this had been an ongoing concern throughout the early years of the American republic, an exchange between Abraham Lincoln and Joseph Hooker shows its connection to the Civil War years. Upon appointing Joseph Hooker to command the Army of the Potomac, Lincoln wrote, “I have heard, in such way as to believe it, of your recently saying that both the Army and the Government needed a Dictator. Of course it was not for this, but in spite of it, that I have given you the command. Only those generals who gain successes, can set up dictatorships. What I now ask of you is military success, and I will risk the dictatorship.”

After the Civil War, the government moved quickly to disband the military to a size that would not be a threat to the civilian government. Yet, there was still the need to occupy the Southern states who held a unique position of both being a defeated “nation” and, as some would argue, still legally part of the United States. This, therefore, created a conundrum in the American constitution. Could federal troops be used to infringe upon states’ self-government?

This became the crux upon which many Reconstruction arguments would be made. Throughout the Reconstruction years, the North argued that the federal troops should remain in place to uphold the laws of the constitution, while the South argued that the continued presence of troops, especially after Southern states were readmitted into the Union, was a threat to democracy and the Constitution. As these states were readmitted into the Union, and as they were “redeemed” through the election of Democratic governments, which were less likely to accept continued federal presence, the fight over the military took place in the Democratic-led House’s attempt to defund the Army.

Part of this fight over the size of the Army occurred during the Hayes administration. As the two parties argued over the 1878 Army Appropriation bill, it was clear to the congressional representatives at the time that the real fight was over the continued presence of troops in the South. After his election, Hayes repositioned troops away from two statehouses, but troops were still stationed in the South and many Southerners viewed this as a threat to their self-determination. 

Democrats argued that federal troops were anathema to the intentions of the founding fathers who abhorred standing armies as a threat to the republic. While Republicans often responded that the military had never been a threat to the democracy and could not withstand the numbers of citizens who would rise up to disallow a military overthrow of the government. For example, William Phillips [R-KS] argued before Congress that the South was “infected with the idea that a military force is dangerous to popular rights, jealous of it because in the ‘late unpleasantness’ they learned to dislike it, carried away by this short-sighted false economy, would reduce our Army to a drummer, a fifer, and a band-master.” His view was that the South “pretend[s] that a United States Army of any kind is a menace to popular liberty; that any military establishment outside of a State militia is pregnant with the overthrow of the civil government.”

While access to the vote was the primary underlying cause for the disagreement over the bill, there was also the question of civilian unrest related to the recent railroad strikes in 1877 in which Hayes used the military, as he argued, to protect life and property. Republicans leaned even deeper into this by arguing that the presence of federal troops would have done even more to prevent the destruction during that uprising.

Ironically, posse comitatus was a statute that the South was willing to dismiss now that it was no longer to its advantage. During the controversial Fugitive Slave Law years, the South leaned on the posse comitatus idea to ensure that escaped slaves would be returned by allowing for U.S. Marshals to call upon citizens to protect the transport of slaves to the South.

While the posse comitatus amendment to the Army Appropriation Bill was a partisan movement, the passage of the Army Appropriation Bill itself was bi-partisan. But, when the bill made its way to the Senate, Senator James Blaine (R-ME) led a lively discussion on this issue arguing that the amendment was unnecessary and not pertinent to Army Appropriations. In the end, both parties depicted the act as an innocuous addition since it still allowed for the use of the military when the Constitution or Act of Congress allowed. Also, the Republican party was in a vulnerable position since a large portion of Americans believed Hayes was elected through electoral fraud. Abram Hewitt (D-NY, and former head of the DNC) unflinchingly argued that the Hayes administration, “reaped the rewards of the abuse of the Army and today occupy positions to which they were never chosen by the people of this country.”

After it made its way through Congress, President Hayes signed the appropriation bill with the amendment attached on June 18, 1878.

What did President Hayes have to say about Posse Comitatus?

While Hayes leaves little information to his thinking upon signing the bill, he references the law later while fighting against Congress over the next Army Appropriation Bill. Democrats in the House wanted to add another rider, this time explicitly preventing any federal military or civil authorities from monitoring the polls. While Hayes was willing to sign the appropriation bill in 1878 with the posse comitatus rider, this one did not provide any language that would have provided supremacy to the Constitution. Moreover, he wearied over the Democratic House attempting to circumvent the president by attaching controversial riders to appropriation bills. While Hayes did not feel a need to use federal troops at the polls, he objected to members of Congress attempting to override the president's right to protect voting during federal elections. He admitted, at this point, that the issue was already settled anyway by the posse comitatus amendment the year earlier. He stated, “No power denied to the army by this bill now belongs to the army. If there was doubt on this question the act of June 18, 1878, removed it.”