Today, Americans focus a great deal on domestic paramilitary groups, such as the Proud Boys or the Three Percenters, who were involved in the attack on the U.S. Capitol in January 2021. However, what many do not know is that paramilitary groups have played a huge role in U.S. politics long before the modern era.

The weirdest and most important of these early paramilitary groups were the filibusters, 19th century Americans who formed armed groups aiming to invade and conquer countries with which the United States was at peace. Filibusters launched invasions of Mexico, Canada, Nicaragua, Cuba, Venezuela, and other countries in the early 19th century.

The most notorious filibuster was William Walker, who in the 1850s invaded and briefly seized control of Nicaragua. The most successful filibuster expedition, however, came twenty years earlier, when armies of filibusters invaded Mexico to aid in the 1835-1836 Texas Revolution. Roughly half the soldiers in the Texas revolutionary forces were not Texan, and had only crossed the border after the beginning of the war in October 1835. While they fought on the Texan side, the filibusters very much looked after their own interests. After the Texan rebels won, the filibusters launched a coup against the fledgeling Texan government and attempted to incite a continuation of war with Mexico.

The strangest filibuster, however, can only be the Patriot War of 1837-1838, when tens of thousands of Americans formed a secret society called the Patriot Hunters. This network of interconnected chapters was dedicated to violently overthrowing British rule in Canada.

 Because of their intense secrecy, little evidence of the Lodges’ organization remains, but a surviving account of their initiation ritual paints a vivid picture. Prospective members were blindfolded and asked to recite a long oath, in which they swore “to do my utmost to promote Republican Institutions and ideas throughout the world–to cherish them, to defend them; and especially devote myself to the propagation, protection, and defense of these institutions in North America,” and to never betray the secrets of the Hunters. One historian described the initiation ritual of the lodges thus: 

After taking the required oath, the Candidate was required to “behold the light.” The bandage was then yanked from his eyes, and he now confronted the sharp edge of a sword pointed directly towards his breast and two pistols being flashed before his eyes. To the eastern lodges a burning torch was to be seen in the background, to symbolize the fire that would burn his house, should he reveal any of the secrets confided in him by the society.

Oscar Kinchen, The Rise and Fall of the Patriot Hunters

Thousands of these armed filibusters crossed into Canada in the genuine belief that the Canadians would rise up and join them. As it happened, the Canadians were fairly content with British rule (or at least preferred it to what the maverick filibusters offered) and British troops crushed all the invasions.

Needless to say, the U.S. Government condemned the illegal actions of the filibusters. Stopping them, however, proved an impossible task. Local governments often provided filibusters with not only muskets, but cannons, uniforms, food, and transportation. American soldiers sent to seal the border against the filibusters sometimes abandoned their posts and joined the filibusters instead. During the Texas Revolution, hundreds of troops abandoned their posts on the Texas border to fight in Texas. As one Texas settler commented, “Deserters they were called, but after the battle, they all ‘deserted’ back to the United States army, and no court martial ensued.”

While many filibuster invasions failed, the filibusters won in the end. Partly in response to the filibuster invasions, the 1840s U.S. government adopted a far more militaristic and expansionist foreign policy, articulated by the famous phrase “Manifest Destiny.” Filibusters, however, had anticipated the movement. Take, for example, what Frank Johnson, a filibuster in Texas, wrote in a declaration to the Texan army.

“To arms! then, Americans, to aid in sustaining the principles of 1776, in this western hemisphere…. Not only Texas and Mexico, but the genius of liberty, demands that every man do his duty to his country, and leave the consequences to God. Our first attack will be upon Matamoros [a city in central Mexico]; our next, if Heaven decrees, wherever tyranny shall raise its malignant form.”

Frank Johnson, 1836

The filibusters raise interesting questions about the politics of early America. How could groups of ordinary citizens have overpowered their own government and set the foreign policy agenda so easily? Was this radical democratization of foreign policy an inevitable outcome of the American political system?

Part of the answer lies in the American military system, which proved an excellent breeding ground for paramilitary groups. Early America had both a minuscule professional military (numbering less than 20,000 men for much of the early 19th century) and a huge system of state militias, which provided hundreds of thousands of Americans with weapon training. In the 1820s and 1830s, however, the states ended mandatory militia service. The shift left the country with large numbers of men with military training but no outlet. Many Americans, therefore, began to found their own private militias. These small, unregulated groups in turn became police forces, slave handlers, frontier patrolmen, and, as it turns out, filibusters.

Filibusters were motivated by a combination of patriotism, racial chauvinism, economic pressure, and the militaristic masculinity of their time. While the filibusters are long gone, their successors continue to draw upon many of these eternal drivers as they influence modern American politics.

Filibusters in the 1830s are the subject of my undergraduate thesis. For those of you interested in a much deeper dive into the subject, the full 100+ page document appears below.