Slaves returning from a cotton field in the American South, early 1860s

Chugging against the current on a boxy steamer, the officer closely monitored the course of the Congo River. You’d think a river might be easier to navigate than the sea, since it flows in one direction and looks, more or less, like a line. You’d think it would be more interesting to look at, and presumably safer, too.

You’d be wrong. Stones, sandbanks, widely varying soundings, sticky heat, banks a monotonous screen of jungle, and the menacing possibility of attack: being on the river was bad enough. And what surrounded it was ghastly, a rapacious imperial system to extract rubber or gold or timber, whose toll the officer had seen in the emaciated bodies, even corpses, of black laborers. The Congo journey was the most psychologically and physically challenging that Joseph Conrad had endured in more than fifteen years of sailing. Later, in the pages of his 1899 novella Heart of Darkness, he described the river as “an immense snake uncoiled,” reaching into a horrifying “place of darkness.”

It’s significant that the best-known indictment of modern European imperialism begins on a river and moves by steamboat. Steamboats were to nineteenth-century empire-builders what caravels had been to the conquistadores, and what satellites and drones are to us: they extended political and economic power into hitherto inaccessible regions. In China, the British East India Company used steam-powered gunboats to wage the Opium Wars and secure access to inland waterways and markets. In the Middle East, steamships opened the Red Sea, Euphrates, and Tigris to reliable commercial navigation, dramatically reducing the travel time between Asia and Europe, and raising European imperial interest in the region. In Africa, river steamers achieved what centuries of coastal trade had not, by penetrating the interior for European commerce—and colonization—up the Niger, the Zambesi, the Nile, and, of course, the Congo.

But it was in North America that “steamboat imperialism” came into its own. It was here that Robert Fulton had first demonstrated the commercial potential of steamships, with boats on the Hudson that could take you from New York to Albany in about thirty hours, while a stagecoach took days. In 1811 Fulton launched the first commercially successful steamboat on the Mississippi. By 1820, sixty-nine steamers plied the Ohio and Mississippi rivers. A generation later, there were 740. Steamboats powered the push of white settlement into Indian territory, and facilitated the commercial development of the Mississippi Valley into perhaps the most profitable land in the world. The “Cotton Kingdom” was created by steamboat imperialism.

Even today’s politically correct textbooks, sensitive to the United States’ genocidal campaigns against Indians, do not conventionally describe America’s continental expansion as “imperialism” in the same vein as early European colonization, or as later US interventions overseas. Yet to the founders, imperialism was precisely what the United States should aspire to—to be an “empire for liberty,” as Thomas Jefferson put it, in which territorial expansion would guarantee the rights of (white) citizens, self-sufficient on their own land. With the Louisiana Purchase he appeared to acquire that empire in one remarkably peaceful and cost-efficient stroke.

But no empire, even a bargain- basement one, comes without a fight. Jefferson and his successors fought alternate settler-led projects for the region, starting with Aaron Burr’s conspiracy to form a breakaway republic. They fought the indigenous owners of the land, hunting down and driving out the Seminole, the Chickasaw, the Creek, the Choctaw, the Cherokee, till the region had been, through “ethnic cleansing,” as Walter Johnson puts it, “converted into a vast reserve for the cultivation of whiteness.”

Soon they fought their own labor force, the slaves whose (real or imagined) insurrectionary threat created a continuous “counterinsurgency campaign to which there could be no end.” In just a generation, Jefferson’s vision of a “republican Arcadia populated by self-sufficient yeomen” had become a nightmare of “slaveholders patrolling the night against an army of slaves they thought outnumbered them fifty to one, lynch mobs closing the courts and arrogating their authority, broken bodies, black and white, swinging side by side from the gallows.” What Conrad saw on the Congo in the 1890s was not so new. It had been anticipated generations before in the imperial conquest of the Mississippi Valley.

River of Dark Dreams evokes what Johnson terms the “slave racial capitalism” at the heart of America’s inland empire. In the antebellum Mississippi Valley, he argues, a nexus of land appropriation, slave ownership, and agrocapitalism took shape that didn’t just put the lie to Jefferson’s “empire for liberty.” By the 1840s, it fostered in turn pro-slavery imperialism whose aims were to shed northern-imposed trade restrictions and engage freely on a world market, to capture new territory in Latin America for white slave-owners, and even to recommence the Atlantic slave trade. In the Mississippi Valley, Johnson argues, “the coming of the Civil War” didn’t play out as a secessionist movement, in which the South asserted what it was not, so much as an expansionist one, inspired by a sense of what the South could be.


Johnson draws inspiration from Marxist scholars including Eric Williams, author of the 1944 classic Capitalism and Slavery, and the geographer David Harvey, a self-described “historical-geographical materialist.” For those uninitiated in this literature, reading Johnson’s book occasionally feels like being the odd person out at a dinner party of old friends. (One chapter, for instance, is entitled “Limits to Capital,” a nod to Harvey’s book of that title.)

The artistry of River of Dark Dreams lies in the close-up—in Johnson’s mesmerizing attention to the “material” in historical-geographical materialism. In the pointillist style so dexterously displayed in his reconstruction of the New Orleans slave market, Soul by Soul, Johnson zooms in on the “nested set of abstractions” that made the Cotton Kingdom run: money, markets, maps, labor. “If you looked more closely,” he observes, “you would see that each abstraction stood at odds with the physical properties of the object it sought to represent.” River of Dark Dreams delivers spectacularly on the long-standing mission to write “history from the bottom up”: from the soil tangy and pungent with manure, and the Petit Gulf cotton plants rooted into it, and the calloused fingers plucking its blooming, sharp-edged bolls. This is a history of how wilderness became plantations that became states, nations, and empires—of how an overseer’s lashes sliced into a slave’s back turned “into labor into bales into dollars” into visions of America’s future in the world.

To begin with, there was water and land. The transformation of the Mississippi Valley into the Cotton Kingdom started with teams of Land Office surveyors who trudged through the swamps with measuring chains “to make the concrete landscape abstract: to turn this salt lick into a salt lick.” “None but men as hard as a Savage” could stand such work, wrote one, going “for Days up to the knees in mud & mire,…drink[ing] any fluids he finds while he is drenched with water also.” Flattened into maps, the land could then be sold off, $1.25 an acre, 160 acre lots, peopled by white owners and black slaves, and planted with cotton.

The land’s richness depended on the river, and more particularly on the steamboats that turned the Mississippi into a commercial highway. Not only did steamers collapse the time it took to get goods to market, they could reliably chug upriver against the current to import goods and people. Anticipating Conrad, who thought that “going up [the Congo] was like travelling back to the earliest beginnings of the world,” Mississippi travelers thought of their passages “as a sort of time travel: a journey backward in history,” into a place of “dark labor darkly concealed.” Enthusiasts saw steamboats as “a deus ex machina” for “imperialism and dispossession” and modernization.

In the words of one (British) traveler, steam navigation propelled this “wild and savage nature” into “a giant infancy, advancing on to manhood with colossal strides.” (Many of the travelers Johnson quotes, incidentally, were British—worth noting given Britain’s double identity at the time as the greatest global champion of abolition and the greatest consumer of American slave-grown cotton.)

Nature nonetheless subverted the abstractions of maps and timetables. The Mississippi changed course so often that you couldn’t use a map to navigate it; instead, pilots had to rely on skill, memory, information, observation. So variable was the river that one captain, who had sailed hundreds of thousands of miles on it, sent helpful notices of the day’s conditions to the New Orleans Picayune and signed them with a pseudonym meaning “two fathoms”—“Mark Twain”—later adopted by the Mississippi’s most famous author. The ships generated hazards of their own. Western riverboats used high-pressure engines powerful enough to propel them over the Mississippi’s sandbars, but that were also prone to explosion. Accidents were common enough for one critic to deplore “the history of steam navigation on the Western rivers” as “a history of wholesale murder and unintentional suicide.” There were more than a thousand serious accidents on the riverboats during their heyday; accidents destroyed 5 percent of tonnage every year; disaster was “a constant topic of conversation among travelers.”

Johnson recreates the grinding, sometimes deadly work of moving in the Mississippi Valley with such originality that it doesn’t much matter that the analytical payoff rests largely in metaphor. Steamboats, he says, were “like bubbles,” “gigantic commercial platforms” that floated on the river like the high-risk markets they served. River pilots were like cardsharps studying their opponents for clues; in Mississippi poker, you “navigated” your hand, and “the final card, dealt face down…was called ‘the river.’” The river itself was like the characters it fostered, a society of gamblers, speculators, confidence men, and runaways who slipped the nets of labor, capital, and race that tightened over their world.


On either side of the Mississippi reached the fields of the Cotton Kingdom. The central portion of the book examines the character and experience of Mississippi Valley slavery. “Slavery” is a term, like “genocide,” whose moral weight threatens to crush its own history. You already think you know—and you certainly know what to think—about the horror of it. The historiographical models appear set—domination vs. resistance, victimization vs. agency, racism vs. apologetics—and the research methods and their pitfalls seem well known. What is an original historian to do?

Johnson approaches slavery by applying literally Marx’s observation that “labour…is a physiological fact,…the expenditure of human brain, nerves, muscles.” “Enslavement,” Johnson demonstrates, “was a material and spatial condition, as much as an economic and legal one.” The preferred strain of cotton in the Mississippi Valley, Petit Gulf, was prized for its “pickability,” which quadrupled the amount an able adult could pluck per day. Planters measured yield by the “hand” as often as they did by the acre, and counted their laborers as “hands,” too: a healthy adult was a “full hand,” a nursing mother a half, a child a quarter. The practice of picking wrought a “forced neuro-muscular transformation” on the slaves, to which some responded by understanding their “labor” as skilled “work,” taking pride in the ways they “came to know and master nature, the knowledge they had in their hands.”


Kean Collection/Getty Images

Unloading cotton from a steamboat on the Mississippi River, circa 1870

Food—more than the lash—served as the everyday instrument of control. Rarely was there enough of it. Slaveholders “converted black hunger into white supremacy” by managing the kind, quantity, and quality of food they delivered. One overseer smelled on a slave’s skin that he was eating meat, and accused him of stealing cotton to trade for bacon. There was little distance on a plantation between slaves and farm animals, physically or conceptually. Slaves got much the same food as animals, and shoveled their own shit to add to the heaps of manure that planters obsessively applied to refertilize the soil. Slaves, too, were branded and had their ears nicked. They, too, were used as breeders. They, too, were flesh, and their “tortures often took place in the slaughterhouses and smokehouses where animal flesh was prepared for human consumption.” If ever they tried to run away, they found themselves adrift in a “carceral landscape” violently policed by horses and dogs.

Whereas Johnson’s analysis of steamboat imperialism turns on metaphor, his detailed description of slavery acts as a rebuke to the oversimple metaphors that are used to describe slaves’ lives and labor: money and markets. After it left the fields, slave-picked cotton got translated into bales in a record book, bales got translated into consignments, consignments got translated into advances and sales, sales got negotiated in an international market by merchants in New Orleans, New York, and Liverpool. The political economy of the Mississippi Valley translated the finger-bleeding, back-bending, crying, singing, hurting labor of slavery into abstract terms of commerce. “When the first handful of cotton arrived in England, half a century ago, could it have entered into the mind of Adam Smith…to conceive that the fleecy cargo…was destined…to make the broad ocean white with ships and trade?” asked the pro-slavery free-trader Matthew Fontaine Maury, a fantastic reworking of forced black labor into a vision of free-floating white.

In these chapters, Johnson interleaves lyrical descriptions with scholarly catchphrases (“landscape-structured bodily power,” “techno- enhanced visuality,” etc.), a practice that can grow insistent. His close reading empowers him, though, to unseat some popular academic characterizations of slavery. The commingling of slaves and animals may seem, for instance, to support historians’ contention that slaveowners “dehumanized” their chattel. But, he writes, “inserting a normative version of ‘humanity’ into a conversation about the justification of historical violence, lets them—and us—off the hook.” In fact, “slaveholders were fully cognizant of slaves’ humanity—indeed, they were completely dependent upon it.” Their power rested in deliberately “dishumanizing” their property, by consistently restricting the forms that slaves’ humanity could take.

Johnson also takes a satisfying swipe at another favorite trope, “agency.” Its forms of resistance “reflected the terms of…oppression”: stealing meat, for instance, as a retort to malnourishment. But for all that

the lives of enslaved people were limited, shaped, even determined by their enslavement…. They recognized their fellow slaves not as “agents,” but as family members, lovers, Christians, Africans, blacks, workers, fellow travelers, women, men, co-conspirators, competitors….

They forged bonds of care and solidarity “that transcended and actively reshaped their enslavement.” A small thing, perhaps, but their own.

No empire for liberty, this—but was it an empire? Whose and how? The final chapters of River of Dark Dreams consider “alternative visions of what ‘the South’ might look like” as this domain, conceived in one imperial vision, grew up to generate expansionist and outward-looking projects of its own.

As Johnson notes, national history sits in such thrall to the spatial teleology of maps that it takes some effort to recall the flexibility of borders in generations past. At the time of the Louisiana Purchase, what we think of as the Deep South was really the Far West. At the time of the Monroe Doctrine, Texas was part of Mexico, and Oregon jointly administered by Britain. At the time of the Gold Rush, the fastest way to get to California involved going south to Central America, crossing the isthmus, and sailing up the Pacific coast.

What all this meant was that, if you looked at the world from New Orleans or Natchez, you didn’t necessarily see the future of your country in the West. In fact, “for white people in the Mississippi Valley in the first half of the nineteenth century, a map of the United States was not complete without the Gulf of Mexico.” They saw expansion into Latin America and the Caribbean as a “revitalizing (spatial) fix” for their particular economic problems and ambitions. Overinvested in “land, slaves, and steamboats,” they wanted more land for white owners, more slaves to work it, and more steamboats, in place of the railroad-driven economy of the East. They hoped to keep the Mississippi River a vital north–south axis for continental and international trade—which, incidentally, they wanted to be tariff-free.

These pro-slavery, free-trade imperialists focused first on Cuba, popularly figured as “Mistress of the Gulf.” They dreamed of liberating it from Spanish misrule and turning it into a commercial hub dependent on New Orleans. The Venezuelan-born Narciso López twice invaded Cuba from New Orleans, with a motley international crew of volunteers. His first invasion ended in a hasty retreat; the second, in 1851, in an almost equally hasty defeat. Leaving one column on the coast to carry the baggage—where they were promptly wiped out by the Spanish—López marched the rest of his men over the mountains. Hot, exhausted, sick, undisciplined, starving, they were soon cornered and crushed. Less than three weeks after landing, López was garrotted in a public square in Havana.

The conquest of Cuba thwarted (for then, at least), Tennessee-born adventurer William Walker championed a fresh project for southern-led empire, this one in Nicaragua. Less than one hundred miles wide at its narrowest, and much of that navigable by river and lake, Nicaragua offered a swift transit from Atlantic to Pacific. In the wake of the California Gold Rush, shipping magnate Cornelius Vanderbilt won a concession to run a steamboat service across the isthmus. Soon, 20,000 people a year were crossing Nicaragua, proving its commercial and strategic value to American commerce.

Walker washed up in Nicaragua in 1855 as a volunteer in an ongoing civil war. Often characterized as withdrawn, effeminate, pallid, slight—by no means the stereotype of a born leader—Walker turned out to be effectively brutal both in the field and in backroom politics. In just a year, Walker vanquished his military and political opposition, negotiated support from Vanderbilt’s partners in the transit business (who meanwhile ousted Vanderbilt), and got himself elected president of Nicaragua. As president, he promptly nationalized the transit business, reopened the slave trade, and made land available to white American immigrants, whom he recruited “with the insistent consciousness-raising of a late-night infomercial” to infuse Central America with white blood. In Nicaragua, as Walker envisioned it, disempowered white southern men could, like him, “be made whole” again.

Walker went down as fast as he’d gone up, unseated by the vengeful Vanderbilt—and when he returned to Central America to try to reclaim his position, he was captured and executed in Honduras. But his preferences—for slavery, for the tropics, for white male privilege—were aligned with a final antebellum vision for the future of the Mississippi Valley. For his intrigues exemplified the fact that “a substitution was taking place.” Instead of “the notion of ‘the South’ as a region within the United States of America, and governed by the laws made by the United States Congress,” increasingly many white southerners saw “‘the South’ as a region defined by its relation to the world economy.” They saw reopening the slave trade as the best way to ensure their economic future.

When Lincoln was elected President eight weeks after Walker’s death, southerners recognized that any slave-owning southern future required secession first. Johnson ends his book one page later. Union victory, he determines, cast the origins of the Civil War “as a national story, one whose temporal and spatial parameters were contained within the limits of the United States,” and erased the expansionist ideas of Mississippi Valley planters. True enough.

Yet is it enough? The chapters on imperialism lack the material richness that memorably characterizes the rest of River of Dark Dreams; the chronology confuses, the arguments grow diffuse, the book ends without a conclusion. This is unfortunate, because it leaves unvoiced a vital argument about the connections between American continental imperialism and American imperialism overseas. For northern victory didn’t just change the way the Civil War was understood; it also rewrote the history of American imperialism. Standard histories of the United States turn on an east–west axis: first America “expanded” west, the story goes, and only afterward did the US become in any way “imperialist,” by considering the acquisition of overseas colonies.

River of Dark Dreams puts paid to such neat (not to say self-flattering) distinctions. Continental US expansion was never completely divorced—conceptually or materially—from the prospect of expansion farther afield. And while historians dispute whether, when, and where to call nineteenth-century American history “imperial”—given a record of genocidal war, slavery, colonization, filibustering, resource extraction, geopolitical rivalry—Joseph Conrad would have recognized it.

With the Thirteenth Amendment the United States finally achieved some more accurate measure of the liberty of which Jefferson spoke. Its expansionist aspirations persisted. As Jefferson had snapped up the Louisiana Purchase for the young nation, the re-United States promptly concluded with Russia a second imperial bargain, the Alaska Purchase of 1867. “Seward’s Folly,” as many scoffed, was made good only a generation later with the lucky strike of Klondike gold. In international geopolitics, however, this noncontiguous accession, leapfrogging British Canada, marked an assertion of continental power on a grand scale, an act of containment against the British Empire.

The southern-looking visionaries of the Mississippi Valley never got their empire for slavery. Instead, mirroring the fate of Revolutionary-era loyalists who resettled in the British Empire, thousands of Confederates traveled as émigrés into the empire they had once hoped to build. Matthew Fontaine Maury, who had fantasized about a sea fleecy with freely traded cotton, emigrated to Mexico and founded the New Virginia Colony as a haven for Confederate refugees. Perhaps ten thousand went to Brazil, attracted by promises of subsidized land in a slave-owning country, while others scattered to Cuba, Honduras, Venezuela. We can be grateful that the expansive hopes for slavery of the Mississipi Valley imperialists ran aground. We would be reckless to forget their connection with the expansive hopes on which the United States still coasts.