How I would have liked to have answered the essay question, “Why did the United States become so much bigger between 1800 and 1850?”—had honesty been an acceptable entry requirement.
To ask why the United States “became so much bigger” between 1800 and 1850 is to speak the language of cartographers and mythmakers—those who prefer the ink of borders to the blood beneath them. This is not the language of justice, nor accuracy. The passive grammar of the question reflects the very ideology it ought to interrogate: the belief that expansion was inevitable, almost geographical, as if rivers naturally flowed westward with muskets and land deeds in tow. But American growth was neither natural nor accidental—it was constructed through law, enforced through violence, sanctified through racial theology, and made profitable through speculative capitalism. The United States did not become anything. It took. It stole, invaded, coerced, and then congratulated itself for doing so.
Treaties were signed with one hand and broken with the other. War was waged in the name of peace. The law, ever obliging, declared that Indigenous peoples could not own what they had already lived on for centuries, while judges in powdered wigs translated conquest into precedent. Elsewhere, ministers blessed the work of rifles, declaring that God had always intended Nebraska for the ploughshare and the cotton gin. The machinery of expansion did not run on courage or conviction, but on contracts, bayonets, and an exquisite ability to forget. By 1850, the nation had not merely grown—it had laid out a blueprint of domination that it would export for the next two centuries.
American law, far from restraining the nation’s territorial appetite, acted as its most polished weapon. Long before soldiers arrived or surveyors drew lines, legislation and jurisprudence had already cleared the moral and administrative path for expropriation. The Indian Removal Act of 1830, passed by Congress and signed by President Andrew Jackson, did not simply encourage relocation—it authorised the federal government to displace entire nations by force under the guise of ‘negotiation’. Its passage marked the institutionalisation of ethnic cleansing in legal form, complete with legislative decorum and a democratic majority. By 1838, under Jackson’s successor Martin Van Buren, the Trail of Tears began: over 16,000 Cherokee were rounded up and marched at bayonet point from Georgia to present-day Oklahoma; at least 4,000 died along the way from exposure, starvation, and disease.¹ This was not a tragic anomaly—it was the intended outcome of a policy built to free land for white settlement and slaveholding agriculture. Liberty needed room to breathe. Legal historian Gregory Ablavsky points out that such laws were less about disorderly frontier pressures than the calculated expansion of federal sovereignty over Native spaces², with Jacksonian democracy serving as legalised empire rather than democratic compromise.
But the legal machinery went deeper than executive action. In Johnson v. M’Intosh (1823), Chief Justice John Marshall ruled that Indigenous peoples held only a right of occupancy, not ownership—a doctrine derived from the Doctrine of Discovery, which claimed that European colonial powers acquired a superior title to land upon discovery, regardless of existing inhabitants. Convenient, that the act of being discovered invalidated centuries of habitation. This decision did not simply reflect settler ideology; it created it. It turned conquest into legal precedent, retroactively laundering the seizure of Native land as an act of jurisprudential order. Land could be bought, sold, and speculated on, because Indigenous presence had been transformed—by law—into a technicality. Whereas Francis Paul Prucha sees decisions like Johnson as reflective of prevailing legal norms and necessary compromise, Robert A. Williams Jr. argues that in Johnson v. M’Intosh, “the rule of law… was circumvented”³ to serve the political interests of the federal government, creating a legal system that “settled the legal status and rights of the American Indian” through doctrines designed to legitimise conquest.
The logic extended beyond courtrooms into the text of treaties, which were drafted, signed, and abandoned with mechanical consistency. The Treaty of New Echota (1835), which led to Cherokee removal, was signed not by the Cherokee government but by a minority faction, under duress. Even so, it was upheld by the U.S. government as binding–evidence, supposedly, of a consensual transfer. One can only admire the bureaucratic efficiency with which fraud was converted into legal truth. The Choctaw, Creek, Chickasaw, and Seminole were subjected to the same strategy: offer a treaty under threat of annihilation, then declare victory when the ink dries. These were not mutual agreements but extortionate contracts executed with legal flair. The entire process—legislative, judicial, and diplomatic—relied on the same foundational lie: that Native Americans were not sovereign, and thus not entitled to territorial integrity. As historian Robert A. Williams Jr. notes, American law “constructed the Indian as a subject without legal title,”³ a strategy that turned conquest into an administrative formality. This wasn’t law as justice—it was law as performance, a ritualised choreography that ensured theft appeared orderly and removal appeared inevitable.
By the 1830s and 40s, this expansionist posture had evolved from opportunism to strategy. Nowhere is this more explicit than in the annexation of Texas in 1845. Sold to the American public as a patriotic reunion, it was the absorption of a former Mexican province that had declared independence to preserve slavery—something outlawed by Mexico. The Republic of Texas had spent a decade as an unrecognised, unstable buffer state before the United States, ever allergic to missed real estate opportunities, decided to make it official. The annexation was less about reuniting wayward brothers and more about expanding the territory available to enslavers. Unsurprisingly, Mexico saw this as provocation.
Enter the Mexican-American War (1846–1848)—a war the United States chose, initiated because Mexican forces had spilt “American blood on American soil.”⁴ The only problem: the soil in question was disputed territory—a landscape between the Nueces River and the Rio Grande that the U.S. had provocatively invaded. Samuel Flagg Bemis, writing from the comfort of mid-century exceptionalism, described American expansion as “peaceful” and achieved “by force of Republican example”—a framing that transmuted conquest into a moral performance rather than military aggression. Amy Greenberg, less enchanted, counters that President James K. Polk engineered the war with theatrical precision—”not despite its risks, but precisely for the lands they might justify.”⁵ The result? The Treaty of Guadalupe Hidalgo, signed in 1848, where the United States acquired what is now California, Arizona, New Mexico, Nevada, Utah, and parts of Colorado and Wyoming—approximately 525,000 square miles⁶, or nearly half of Mexico’s national territory. In return, the U.S. paid $15 million, as if to preserve the illusion of a fair exchange. That sum, equal to roughly $600 million today⁷, breaks down to about four cents per acre. Even by 19th-century standards, this was a paltry value, especially given that California’s gold was discovered just weeks earlier. The payment wasn’t restitution—it was theatre, meant to preserve the illusion of a legal exchange while formalising what was, in essence, imperial seizure. The treaty included a formal promise to respect the property and rights of Mexican nationals in the newly seized territories. These promises, like so many before them, were promptly ignored. Mexican landowners were dispossessed through legal sleight-of-hand, English-only court proceedings, and bureaucratic attrition.
Even those territories acquired without open war were not bloodless. The Adams–Onís Treaty of 1819 is often celebrated as a diplomatic marvel in which Spain ceded Florida to the United States. What this version omits is that Andrew Jackson had already invaded the territory, ostensibly to punish Seminole “raiders”, but in practice to assert American control and eliminate Black Seminole communities who had carved out autonomous settlements. Jackson executed two British nationals, razed villages, and presented Washington with a fait accompli. The treaty came afterwards, not as prelude to acquisition, but as postscript to aggression. Spain, weakened and disinterested, formalised what Jackson had already made fact on the ground. It was diplomacy by occupation. The accompanying map (Figure 1) in Claudio Saunt’s Unworthy Republic visually disputes the myth of empty prairies awaiting settlement. It reveals a sovereign and deeply rooted Native presence that U.S. policy dismantled through armed pressure and legal erasure. As the map shows, the Chickasaws and Choctaws held territory equal to half of Mississippi, while the Cherokees, Creeks, and Seminoles controlled vast tracts across what are now Georgia, Alabama, and Florida—lands later overwritten by the fiction of lawful acquisition.
However, the enlargement of the United States was never merely territorial—it was theological, anthropological, and racialised from inception to execution. There was no need for nuanced legal arguments or complex geopolitical debates when Americans already had a universal solvent: the conviction that white Protestant civilisation was synonymous with progress, and everything else a delay of destiny. This wasn’t a fringe belief or the fever dream of backwoods preachers. It was a governing principle, operating across Congress, the courts, the press, and the pulpit.
In 1845, when John L. O’Sullivan coined the phrase “Manifest Destiny,” he wasn’t theorising—he was describing the ideological status quo. It was, he wrote, America’s divine obligation to overspread the continent “for the development of the great experiment of liberty.” That this “liberty” required the displacement or destruction of entire peoples was a minor technicality. As Anders Stephanson argues, Manifest Destiny functioned less as a coherent policy than as a quasi-religious ideology, rooted in Protestant millenarianism and premised on the belief that American expansion was a divinely sanctioned mission.
O’Sullivan’s wording was hardly original. By the time his phrase caught on, the United States had already been justifying expansion through racial typologies for decades. Government land surveys, military correspondence, and Congressional records routinely described Indigenous peoples as “wandering,”⁸ “savage,”⁹ “vagrants”¹⁰—precisely the language required to nullify their land claims. This was no careless prejudice; it was a coordinated epistemology. Under the prevailing interpretation of Lockean property theory, which saturated American political discourse, only land that was being “improved” could be justly owned. Cultivation equalled legitimacy. Which is why it became so vital to pretend that Native agriculture didn’t exist—even when it very clearly did. Cherokee farms, Choctaw irrigation systems, Creek trade networks: all had to be erased or ignored to preserve the illusion of vacant terrain.
As Paul Frymer argues, drawing on Michael Rogin, American empire was animated by a foundational racial logic: conquest was inseparable from the construction of racial hierarchy.¹¹ Rogin contends that racism did not merely accompany imperial expansion—it energised it, providing white settlers with a sense of entitlement, pride, and moral duty under the banner of the “white man’s burden.” Within this symbolic order, Native Americans were not recognised as historical agents or rightful possessors of land, but were reimagined as static, pre-civilisational obstacles to progress. Their erasure was achieved not just through physical displacement, but through what Rogin would identify as ideological domination: a racialised mythology in which terra nullius and “improvement” became euphemisms for conquest. To “improve” land was not a neutral act of cultivation, but a performative assertion of whiteness—making violence appear as virtue, and dispossession as destiny.
Racial ideology wasn’t just useful—it was operational. It turned war into benevolence, displacement into reform. In the case of Mexico, the racial hierarchy was even more explicit. Anglo-American politicians, diplomats, and editorialists framed Mexicans as not only racially inferior but permanently incapable of rational governance. In 1836, amid rising calls for Texan independence, American expansionists did not simply claim land—they performed a resurrection. The Anglo-Saxon race, proclaimed Le Correspondant, would “flow unchecked over the fair provinces where the people, descendants of the conquering Spaniards, have allowed themselves to slumber in corruption.”¹² It was not conquest, but cleansing. Not theft, but inheritance delayed. The Mexican presence was reframed as absence—an abdication of civilisational duty. In the rhetoric of Manifest Destiny, Mexico was not dispossessed. It had dozed off. And so the Anglo-American settler came—not as invader, but as alarm clock.
Even official U.S. envoys such as Joel Poinsett (after whom the Mexican poinsettia flower is named, for irony’s sake) described Mexicans as “ignorant and debauched,” a condition he claimed was engineered by Spanish colonialism and passively sustained by their backwardness. In his words, the nation had “not advanced one step in knowledge and civilisation”¹³ since the age of conquest. This was not commentary—it was imperial diagnosis, justifying intervention through a logic of inherited inferiority.
Religion sharpened the racial blade. Protestant evangelical groups—notably the American Home Missionary Society, the American Board of Commissioners for Foreign Missions, and smaller frontier Presbyterian and Methodist sects—flooded western settlements with sermons that conflated territorial expansion with divine will. Indigenous spirituality was dismissed as satanic animism; Mexican Catholicism, branded superstitious and tyrannical, was described as an obstacle to true moral enlightenment. Missionary newspapers routinely published editorials demanding that American settlers bring “Christian order” to “the wilderness,” a phrase that conveniently erased the hundreds of existing Indigenous theologies and ceremonial traditions.
Circuit preachers—often unlettered but ideologically reliable—framed the conquest of the West as a holy war, and settlers in Missouri and Arkansas listened with conviction. As Mark Noll shows in America’s God and America’s Book, Protestant theology and biblical narrative were central to the ideology of Manifest Destiny, with Americans reading the Old Testament’s “promised land” as a divine mandate for westward expansion—baptising conquest in biblical authority and blending evangelical fervour with republican nationalism to manifest it as moral inevitability.
The press did not merely document American expansion—it choreographed it. Newspapers like The New York Herald and Harper’s Weekly served as ideological projectors, casting settler violence in the soft light of civilisational necessity. In its retelling of the Battle of Little Bighorn, the Herald seamlessly fused “Indians, African Americans, radicals, Catholics, foreigners, and lower-class whites”¹⁴ into a single monolithic threat—transforming racialised others into interchangeable spectres of disorder. This was not journalism; it was cultural triage, designed to render settler aggression as a defence of order.
Harper’s Weekly, for its part, perfected the genre of anthropological spectacle. In its 1858 coverage of Seminole leader Billy Bowlegs, the magazine indulged in ethnographic theatre—mocking his family, appearance, and supposed drunkenness, while documenting his forced removal to Arkansas with the detached amusement of a travelling correspondent reporting on curiosities.¹⁵ Bowlegs is stripped of agency, cast not as a resisting leader but as a comic relic of a fading people. His interpreter, Ben Bruno—a Black man enslaved by Bowlegs—is framed as a foil: described admiringly for his “civilised” dress and manners, yet only as a function of proximity to whiteness. The article implicitly sets up a hierarchy of assimilability, where Black refinement is framed as proof of the Seminoles’ inferiority—re-inscribing both groups within a colonial logic that rewards submission and punishes sovereignty.
The hypocrisy of Harper’s Weekly is best captured in the work of its own illustrators. Even decades after emancipation, the magazine continued to aestheticise racial violence under the guise of moral satire. In A. B. Frost’s 1876 cartoon “In Self-Defense,” a white man looms over the corpse of a Black child, pistol still smoking, declaring, “Ef I hadn’t-er killed you, you would hev growed up to rule me.” The image masquerades as anti-racist commentary but reproduces, almost lovingly, the visual vocabulary of white supremacy: the heroic stance, the grotesquely infantilised victim, the paternalistic justification of murder. Harper’s Weekly thus managed to condemn racial violence while simultaneously circulating its imagery as entertainment. The cartoon’s irony depends on the audience’s familiarity with racist tropes—it presumes complicity in order to indict it, ensuring that the visual grammar of domination remains intact even in critique.
This dynamic is echoed visually—though on a mythic scale—in John Gast’s 1872 chromolithograph American Progress (Figure 3), an unapologetic advertisement for Manifest Destiny disguised as allegory. Gast’s painting does not merely illustrate expansion; it sacralises it. The central figure, Columbia, is a robed embodiment of white civilisational virtue, striding westward with the tools of conquest: a schoolbook, telegraph wire, and star of empire. Her gaze is fixed forward—not on the people beneath her—suggesting that history, when properly directed, requires no reflection. The Indigenous peoples she displaces are cast in shadow, reduced to silhouettes retreating into an obscured wilderness, along with buffalo, bears, and wolves.
Their dispossession is aestheticised into natural law, a kind of ecological inevitability. Even the clouds obey this logic: the West is dark and chaotic, while the East glows with maritime commerce, railroads, and agrarian virtue. Gast, a relatively obscure Prussian-born immigrant painter and lithographer, was not known for radicalism; this was commercial art designed to sell the fantasy of progress to a white settler public. He produced the image for George Crofutt, a publisher of railroad guides, who disseminated it widely as a kind of visual scripture for westward movement. What makes the painting so insidious is that it erases violence through idealism: no blood is shed, no treaties are broken, no screams are heard. Instead, conquest becomes choreography—an elegant ballet of destiny performed in the name of civilisation. In this rendering, education is displacement, femininity is imperialism, and motion itself is morality.
The press, then, was not an external observer of Manifest Destiny—it was its evangelist, baptising conquest in ink and binding racial supremacy to the logic of progress. Through both ink and image, American culture rehearsed its own innocence, training the public to see territorial theft not as theft at all—but as providence, pedagogy, and patriotic fulfilment.
As historian Reginald Horsman notes in Race and Manifest Destiny, the period between 1820 and 1850 saw the crystallisation of an American identity premised on Anglo-Saxon exceptionalism. Scientists, theologians, policymakers, and writers all contributed to the myth that white Americans had evolved to administer liberty more effectively than any other group on earth. This belief didn’t just rationalise expansion—it demanded it. Every delay in occupying the West, every treaty signed in restraint, was framed as a betrayal of a higher duty. In Horsman’s analysis, this racial theology formed the spine of U.S. policy—a “moral mandate” not to coexist, but to replace.
The arithmetic of real estate also drove expansion. The federal government functioned as a land brokerage firm in all but name, absorbing territory through violence or purchase, subdividing it into salable parcels, and offloading it for revenue and political gain. Every acre added to the republic’s map was also added to its balance sheet.
Speculation did not replace conquest—it monetised it. The Land Act of 1804 allowed already-inhabited land to be subdivided, sold, and developed before settlers ever arrived, ensuring that dispossession remained profitable even before the land was populated. Infrastructure was tailored to support this model. The Erie Canal, completed in 1825, transformed the economic geography of the interior, reducing freight costs by more than 90% and creating a real estate bubble across New York, Ohio and Indiana.¹⁶ Land values in canal-adjacent counties skyrocketed. But what was framed as democratic development was, in practice, a blueprint for extraction.
Railroads took this one step further. In 1850, Congress granted 2.6 million acres¹⁷ of federal land to the newly formed Illinois Central Railroad, not for public benefit, but to finance construction by selling the surrounding land at speculative prices. The tracks opened territory not to ordinary Americans, but to venture capital backed by legislative favour.
The discovery of gold in California in 1848 accelerated this economic logic into overdrive. Migration followed minerals, and within a year, the federal government had reorganised the West to accommodate it. California’s sudden leap to statehood in 1850—bypassing the territorial phase altogether—was not an act of governance. It was a financial safeguard. Meanwhile, Indigenous Californians were pushed out or exterminated, not by federal decree but by entrepreneurial militias funded by settler syndicates and retroactively reimbursed by the state.
As Walter Johnson writes, “The land that enslaved people planted in cotton and which their owners posted as collateral was Native American land.”¹⁸ Expansion was not merely coincident with slavery—it was structured around it. The removal of the Creek, Choctaw, and Cherokee in the 1830s wasn’t simply about ‘security’—it was about economics. Cotton exhausted soil. Plantation owners needed fresh ground. The newly cleared land became the Black Belt, the most profitable cotton-producing region in the world. Jacksonian policy didn’t enable expansion—it serviced the plantation economy. Capitalism and slavery, in Johnson’s view, were not adversaries but co-conspirators, entwined in the creation of an imperial market built on commodified life.
The United States became so much bigger between 1800 and 1850, not because it was destined to, but because it had the means, the motive, and no meaningful resistance. Land was power. Law was camouflage. Race was rationale. The republic expanded not through manifest destiny, but through methodical dispossession—legally engineered, militarily enforced, and economically incentivised. Indigenous sovereignty was erased by precedent; Mexican territory was annexed by provocation; capital flowed westward and dragged the state with it. Expansion was not an effect of American exceptionalism—it was its blueprint.
As Alexis de Tocqueville observed in 1831, “The American is devoured by the longing to make his fortune; it is the unique passion of his life.”¹⁹ He might have added: and he will redraw the map to do it.
Sources:
¹ “Our Journey.” Remember the Removal. Cherokee Nation. Accessed July 2025. https://cherokee.org.
² Gregory Ablavsky. “Beyond the Indian Commerce Clause.” Yale Law Journal 124 (2015): 1059–82.
³ Robert A. Williams Jr. The American Indian in Western Legal Thought: The Discourses of Conquest. Oxford University Press, 1990.
⁴ Robert A. Williams Jr. Western Legal Thought. Oxford University Press, 1990, 163.
⁵ Amy S. Greenberg. A Wicked War: Polk, Clay, Lincoln, and the 1846 U.S. Invasion of Mexico. Vintage Books, 2013, 54.
⁶ “Treaty of Guadalupe Hidalgo.” Library of Congress. Last modified September 2020. https://loc.gov.
⁷ “Inflation Calculator.” OfficialData.org. Accessed July 2025. https://officialdata.org.
⁸ U.S. Senate Journal, 10th Congress, 2nd Session, December 30, 1808, 313. https://congress.gov.
⁹ Andrew Jackson. “Message to Congress on Indian Removal.” December 6, 1830. National Archives (NARA), RG 46.
¹⁰ U.S. House Journal, 10th Congress, 1st Session, December 7, 1807. https://congress.gov.
¹¹ Paul Frymer. Race, Class and Empire. Unpublished manuscript, Princeton University, citing Michael Rogin, Fathers and Children: Andrew Jackson and the Subjugation of the American Indian. Vintage, 1975.
¹² Justin H. Smith. The War with Mexico, Vol. 2. Macmillan, 1919, 300, citing Le Correspondant.
¹³ Joel R. Poinsett. “The Mexican Character.” In The Mexico Reader: History, Culture, Politics, edited by Gilbert M. Joseph and Timothy J. Henderson, 2nd ed. Duke University Press, 2022, 13–16.
¹⁴ Arnold Krupat. Review of The Newspaper Indian: Native American Identity in the Press, 1820–90, American Literature 71, no. 4 (1999): 801–802.
¹⁵ “Billy Bowlegs in New Orleans.” Harper’s Weekly, June 12, 1858.
¹⁶ Erie Canalway National Heritage Corridor. “History & Culture.” https://eriecanalway.org.
¹⁷ Statutes at Large, Vol. 9 (1850): 466–67; Paul W. Gates, The Illinois Central Railroad and Its Colonization Work (Harvard University Press, 1934), 14–98; John F. Stover, History of the Illinois Central Railroad (Macmillan, 1918), 16–84.
¹⁸ Walter Johnson. “To Remake the World.” Boston Review, February 1, 2017. https://bostonreview.net.
¹⁹ Alexis de Tocqueville. Democracy in America, Vol. 1. 1835.