The 1878 Act That Barred Federal Troops From States

When the Civil War ended, Congress dissolved the governments of the former Confederate states and placed them under martial law. Even after Southern states were readmitted to the Union, federal troops were frequently deployed to the South during Reconstruction. They were sent to resolve political disputes and to combat groups like the Ku Klux Klan that violently opposed equal rights for Black men, including the right to vote.  

For Southern Democrats, the continued presence of federal troops—particularly Black soldiers—was not only humiliating but also a breach of the Constitution. In 1878, a divided Congress debated whether the president could deploy federal troops in peacetime on U.S. soil. The result was the Posse Comitatus Act, which bars the deployment of federal troops in the states except in times of insurrection or rebellion. 

“Posse comitatus” is a Latin phrase meaning power of the county. It’s a legal term borrowed from British common law for a group of civilians mobilized by a sheriff to enforce the law. In Hollywood Westerns, it's simply called a posse.

In arguing for the Posse Comitatus Act, southern politicians objected to the use of federal troops as a posse to enforce Reconstruction-era laws. Ironically, those same Southern states had supported federal posses before the Civil War to capture runaway slaves.  

Under the Fugitive Slave Act of 1850, slave owners could issue arrest warrants executed by U.S. marshals. The federal marshals, in turn, had the authority to summon a posse of civilians who were bound by law to assist in the enslaved person’s capture. 

Racial discrimination and violence did not end with the Civil War. Under the Reconstruction Acts, Congress deployed the U.S. military to force former Confederate states to comply with the 13th, 14th and 15th Amendments outlawing slavery and establishing equal rights for Black men.  

Those efforts met fierce resistance, resulting in the passage of the Civil Rights Act of 1871 (also called the Ku Klux Klan Act), which gave the president even more authority to use federal troops to safeguard civil rights.  

Military interventions in the South, however, were often unsuccessful. For one thing, there weren’t enough troops to effectively do their job—most U.S. soldiers were battling Indigenous tribes on the Great Plains. On top of that, the military frequently became embroiled in messy political fights.  

In Louisiana, for example, a Republican governor named William Pitt Kellogg came to power in 1872 after a Republican judge invalidated election results that had given the race to a Democrat. Rioting ensued, and President Ulysses S. Grant—in a controversial move—deployed federal troops to help install the Republican governor. Grant called the affair a “miserable scramble.”  

By the mid-1870s, even Northerners were growing weary of the military enforcement of Reconstruction. Wavering public support for military intervention was reflected in the 1874 midterm elections, in which Republicans suffered heavy losses and Democrats took control of the House of Representatives.  

The fight over the presence of federal troops in the South reached a climax during the 1876 presidential election. Once again, federal troops were tasked with protecting Black voters from intimidation and discrimination, but instead they became embroiled in a political scandal. Southern Democrats accused the military of being part of a scheme to "steal” the election for Republicans.  

The 1876 election was the closest in U.S. history. As the electoral votes were tallied, both candidates—Republican Rutherford B. Hayes and Democrat Samuel Tilden—declared victory. Three Southern states, however, had contested results: Louisiana, Florida and South Carolina. When Republican-controlled legislatures handed each state to Hayes, Democrats cried foul.  

The 1876 election was ultimately decided by a special commission that declared Hayes the winner by exactly one electoral vote. To appease Southern states, Hayes agreed to the Compromise of 1877, in which he promised to remove federal troops from the South.  

With Northern support for Reconstruction wavering and Democrats in control of the House, Southern politicians saw an opportunity to outlaw the presence of federal troops for good.  

The charge was led by Representative William Kimmel, a Democrat from Maryland. In speeches on the House floor, Kimmel invoked the Founding Fathers’ distrust of standing armies in peacetime. Kimmel also argued that the Constitution’s “war powers” clauses only allowed the president to deploy the army against foreign enemies or in times of open rebellion.  

While Kimmel vowed that his campaign was “without partisan bias,” the issue of federal troops in the South was deeply political. Both Republicans and Democrats knew that without military oversight, Southern states would engineer ways to deny the Black vote, essentially handing all state offices to the Southern Democrats.

With the disastrous 1876 election fresh in their minds, though, Congress passed the Posse Comitatus Act with bipartisan support and Hayes signed it into law June 18, 1878. The act effectively signaled the end of Reconstruction in the South and opened the door for discriminatory Jim Crow laws that stripped Black Southerners of their constitutional rights.