No one gives abolitionist John Brown credit as an economist. His plan to free four million enslaved in the South stood on a foundation of economic theory.

This theory demands several uncomfortable acknowledgments. By legal definition, an enslaved person is considered property. Sanctioned for thousands of years, humans have subjected other humans to bondage for most of human existence. The Greeks enslaved people, as did Romans, Jews, Christians, and Muslims. Entire conquered civilizations became enslaved. Not until about 200 years ago was this practice broadly challenged, commencing with reformers in England during the early 19^th century.

John Brown ascribed to “all men are created equal,” immortalized in the words of the Declaration of Independence. “[S]lavery throughout its entire existence in the United States is none other than a most barbarous, unprovoked, and unjustifiable war of one portion of its citizens upon another,” Brown believed. “[T]he only conditions of which are perpetual imprisonment and hopeless servitude or absolute extermination; in utter disregard of those eternal and self-evident truths set forth in our Declaration of Independence.”

This antislavery dictum was included as the preamble to a constitution adopted during a convention of former enslaved and free Blacks organized by Brown in Chatham, Canada (May 8, 1858). Its purpose was to serve as the governing ordinance in Southern territories where Brown’s guerilla army of liberators would operate.

But what was his plan? Bankrupting the oligarchy that depended upon enslavement. Investment in slaves as property was costly. An enslaved male, age 18, designated as a laborer, averaged $1,600 at auction by the 1850s. Since most Americans earned only $300 annually, the purchase of just one enslaved person required more than five years of savings. If that investment vanished, or dozens of enslaved persons disappeared one night, or hundreds escaped from a plantation into the mountains, one word would pummel the slave owner: bankruptcy.

Here was Brown’s economic formula. The sudden disappearance of enslaved—aided by, protected by, and directed into the North by Brown’s band of guerillas—would destabilize slave values. Panic would ensue. Those who owned the disappeared “property,” like rattled Wall Street investors, would experience a precipitous decline in prices. Since enslavers had more money invested in enslaved than in their cattle, crops, and castles combined, sudden depreciation of enslaved property would decimate the slave aristocracy’s wealth. Slavery would die because economics killed it.

“I readily saw that this plan could be made very effective in rendering slave property . . . valueless by rendering it insecure,” approved Frederick Douglass, an ardent ally of Brown’s economic doctrine. “Men do not like to buy runaway horses, nor to invest their money in a species of property likely to take legs and walk off with itself.”

Walking off, prior to Brown’s concept, was dangerous. The Underground Railroad, as a physical route of escape, was a hazardous journey. Southern states offered minimal safe-houses and shelters, and enslaved families seldom could flee together. Large groups almost never escaped in concert as it would make detection too easy. And in case of discovery, the freedom seekers had no form of self-defense.

Brown’s strategy corrected these shortcomings. His armed and trained guerilla soldiers, stationed upon mountain ridges at fortified refuges along the Appalachians, would protect escapees as they journeyed from slave country into the sanctuary of the North. The Appalachians, which stretch 1,500 miles from Alabama to Canada, offered an avenue to freedom, passing through eight Southern slave states. If anyone attempted to impede Brown’s plan, violence would be sanctioned. Brown was at war against slavery.

“God had created [me] to be the deliverer of slaves,” Brown believed, “the same as Moses had delivered the children of Israel.”

Brown, himself, proved his plan could work, without violence. Just before Christmas 1858, the abolitionist raided and liberated 11 enslaved people in Missouri—repeatedly hiding and escorting them from Kansas to Detroit—where he saw them off to Canada. Brown’s experiment excited turmoil in the proslavery press, convincing him that an invasion of the South’s largest slave state—Virginia—could reap unparalleled rewards.

Brown implemented his grand strategic plan 10 months later. First, he selected an Underground Railroad center in Chambersburg, Pennsylvania, as his base of operations. Here, surrounding Franklin County bordered the Mason-Dixon Line, the symbolic barrier between bondage and freedom. Brown then established a temporary headquarters at a remote site called the Kennedy Farm in Washington County, Maryland. From here, he could easily strike his first target: Harpers Ferry and the U.S. Arsenal—the principal source of weapons for his army of liberation.

Harpers Ferry terminated Brown’s military and economic strategy. Captured and imprisoned after a failed attack, Brown was stripped of his sword. But not his words.

Brown’s final verdict led to widespread publicity, his execution, and international status as an abolitionist martyr.