The United States’ march across North America to establish a transcontinental republic seems, in retrospect, almost preordained. In the American Revolution’s aftermath, there was no shortage of Americans who looked westwards and envisaged the new country’s eventual expansion to the Pacific. Indeed, one factor contributing to the outbreak of the War of Independence had been Britain’s attempts to prevent American colonists from settling in the North American territories acquired from France following Britain’s victory in the French Indian War and the signing of the Treaty of Paris in 1763.

The story of how America eventually acquired these territories, and the economic, political, and constitutional questions that required navigation before this massive expansion of the American republic could occur, are addressed comprehensively in a new book by the historian Susan Gaunt Stearns. In Empire of Commerce: The Closing of the Mississippi and the Opening of Atlantic Trade, Stearns places commercial expansion to the West at the heart of the political and constitutional debates that preoccupied Americans from 1776 until Napoleon sold France’s reacquired Louisiana territory to the United States in 1803. Stearns’s book is an impressive work, not least because it shows how the forces unleashed by commerce helped give America its current political and geographical form. “At the heart of nascent ideas of American empire,” Stearns argues, “was trade.”

Loyalties Abound

The thirteen colonies’ defeat of Britain in the War of Independence, Stearns stresses, did not clear a path for an effortless American progression toward the Pacific. For one thing, Spain stood in the way. The Spanish Empire controlled most of the Midwest and Southwest, including Florida and the massive Louisiana territory ceded to Spain in 1762 by France. It was by no means obvious that Spain would make way for Americans anxious to acquire land in the West. Nor had Britain and France lost interest in these parts of North America.

Another obstacle to American expansion was disagreement among Americans themselves about the character and extent of any westward enlargement that might take place. The newly independent states were far from being on the same page about such matters, not least because they often perceived their trading interests differently. Moreover, thanks to the highly decentralized constitutional arrangements under the Articles of Confederation, forging a common policy concerning America’s relationship with the Spanish Empire (or any other country) was always going to be difficult for the thirteen states. By the mid-1780s, there was a real possibility that disagreements between the states over trade and foreign policy would splinter the Confederation.

Alongside these dilemmas loomed another issue that features significantly through Stearns’s book: questions of identity, loyalty, and national allegiances. Stearns opens by pointing out that no less than a future president of the United States, Andrew Jackson, was one of eighteen Americans who swore allegiance to His Most Catholic Majesty, King Carlos IV of Spain, before Don Manuel Gayoso de Lemos, the district governor of Spanish Natchez (today’s southwest Mississippi) in 1789. Strictly speaking, Stearns points out, Jackson was not an American in 1789. Instead, he mirrored the shifting identities of residents on the borderlands of the Mississippi River Valley as they sought economic opportunity and embraced whatever political allegiance that they judged likely to bring them closer to this goal.

Jackson and the more than 100,000 settlers who had moved into Western territories over the previous decade, however, faced a major impediment to their ambitions. Five years earlier, Stearns notes, Spain had “closed the Mississippi to American trade,” thereby foreclosing “the possibility of Western produce reaching eastern markets.” This created friction not just between Spain and those whom Stearns calls “Westerners” of the trans-Appalachian West, but also between those Westerners and the new US government established in 1789. Western settlers expected the federal government to make Spain reopen the river to American traffic. Failure of the US government to do so, Stearns states, could have led to Western settlers choosing to exit the Union.

At the same time, fully integrating Westerners and their emerging governance structures into the United States presented another set of challenges. As new Western states acquired representation in Congress and started voting in federal elections, they had the potential to upset the delicate political balance between northern and southern states so painfully hammered out during the 1787 Constitutional Convention.

Stearns holds that the economic drive to the West and America’s subsequent geographical expansion created what amounted to an American empire that “depended on the creation of a system of governance that would allow regions at a distance to become integrated into a centrally focused commercial network.” That system, Stearns shows, was one heavily shaped by reaction to circumstances but also often messy negotiations between political elites inside and outside the United States.

What emerged, Stearns maintains, was less a vision of America in which a national center bound together disparate states and distant territories “like the spokes of a wheel,” than arrangements underpinned by hard-headed trade considerations. These, she maintains, tied “the United States together and allow[ed] for the continued expansion of an American empire float[ing] along the Mississippi.”

Politics and Persons

Stearns tracks international and domestic politics closely throughout this book. But so too does she follow the lives of those European Americans and others in the Mississippi region, such as those of the Chickasaw tribe who lived far from the centers of political power. The economic and personal ambitions of Western settlers were deeply affected by the Mississippi River trade and the multifaceted struggle between America and European powers to control it.

Stearns unpacks her intriguing combination of high politics and personal dramas in three parts. The first looks at how commercial activity and the inflow of migrants from the East shaped European commerce in the West from before the War of Independence until Spain declared the Mississippi closed to American trade in 1784.

Part Two focuses on the years following that closure, examines Congress’s response, and analyzes how the political and economic influences associated with what was called the “Mississippi Question” shaped the US Constitution’s drafting and ratification. While Congress was initially united in its opposition to Spain’s action, Stearns shows how it quickly became divided.

Northern and eastern states prioritized securing freer entry of their merchants into the Spanish Empire’s vast global markets over insisting on access to the Mississippi. Southern states, by contrast, had “extensive claims to western lands and constituents who had invested heavily in those regions.” The subsequent conflicts between these states and their inability to resolve them highlighted, according to Stearns, “the weaknesses of the Articles of Confederation and the necessity of political transformation.” The Mississippi Question was not the only factor leading to the 1786 Annapolis Convention and the 1787 Constitutional Convention. Nonetheless, Stearns demonstrates that it helped spur the states towards embarking upon a constitutional reconstruction that produced the more unified republic that exists today.

The third part of Empire of Commerce considers how the economies of the Western territories were integrated into America’s national economy and that of the wider Atlantic world as a result of the 1795 Treaty of San Lorenzo (Pinckney’s Treaty) before being politically solidified via the Louisiana Purchase. Securing the Western settlements’ access to markets, defining the border between the United States and Spanish territories, and guaranteeing Americans’ freedom to travel all the way down the Mississippi to New Orleans had the effect of spurring fresh influxes of people and capital from the eastern states to the frontier. Crucially, these political successes also cemented the loyalty of Western settlers to the United States.

Stearns’s focus on decisions made by American, British, French, and Spanish officials in all three parts is complemented by careful attention to the lives of ordinary people who, for all their obscurity, were as integral to the story as Thomas Jefferson and Napoleon. Anne McMeans and her family, for example, were smallholders from Western Pennsylvania. Like thousands of other poor families, they undertook enormous risks to seek their fortune first in Kentucky before, in desperation, joining an expedition and journeying down the Mississippi to attempt to settle in what was Chickasaw country.

Through McMeans’ story and those of other settlers, we see how Lockean notions of property bolstered people’s economic hopes but also created clashes with Native American peoples. In this respect, the legal doctrine of preemption, or right of first occupancy, Stearns states, played a significant role. This idea was grounded upon John Locke’s theory that one acquired property by mixing one’s labor in it. That suited those Americans looking westward at lands that were “wasted” insofar as they were understood to have no labor yet mixed into them. Such lands were therefore viewed as open to being acquired as property by whoever got there first. But this doctrine, which fueled the economic expectations of settlers like McMeans, took no account of Indigenous nations’ claims to the same land. The stage was thus set for substantial conflicts of ideas and, ultimately, people.

Constitutionalism Encounters Economic Realpolitik

Stearns’s account of the politics and legal dynamics surrounding this period of economic change ends with the Louisiana Purchase. Having reacquired the Louisiana territories from Spain via the third Treaty of Ildefonso in 1800, Napoleon’s France was in a position to undo all that America had achieved in the area of the Mississippi trade since 1795. Should the French Republic decide to block commerce on the Mississippi, issues viewed as long settled might be put back in question.

It was fortunate for President Thomas Jefferson, Stearns observes, that the Westerners were Democratic-Republicans and that “support for Jefferson was nearly absolute.” This disposed Westerners to wait for the federal government to act. But Stearns underscores that the preceding eight years of stable commerce and growing Western integration into America’s eastern markets had established a commonality of interests and sentiments between Westerners and the rest of the United States. Thus, Stearns emphasizes, obstruction of the Mississippi trade “was no longer a ‘western’ problem.” All Americans now saw themselves as having a stake in it.

Yet such oneness of mind did not provide immediate guidance about what the United States should do about this sudden reinsertion of French sovereignty into the North American continent. Since 1792, the United States had tried to avoid taking sides in Britain and Revolutionary France’s increasingly global struggle. Absent, however, some type of settlement with France concerning the Mississippi trade, America might have to resort to force. That would have necessitated a US alliance with Britain. Though this might have secured the Mississippi trade for America, exiting a war is never as easy as entering it.

In a way, Napoleon’s realization that defending Louisiana was beyond France’s military and naval capacities saved America from having to take such action. Perhaps the greatest irony of Napoleon’s decision to sell 828,000 square miles of French territory to the United States—effectively doubling the size of the country—was the bind in which the Louisiana Purchase placed that strictest of constitutionalists, Thomas Jefferson.

It took a mere three weeks, Stearns writes, “to resolve a problem the nation had confronted for the previous two decades and to transfer millions of acres and tens of thousands of people to nominal US sovereignty” through a deal financed, paradoxically enough, by a British bank. Nonetheless, Stearns comments, Jefferson well knew that “nowhere in the Constitution was he given the power to purchase land.” A constitutional amendment was one way of resolving the legal problem, but the five state legislatures then controlled by Federalists were unlikely to ratify it.

No president or senate was going to decline an opportunity that Andrew Jackson described in a letter to Jefferson as one “which places the peace, happiness, and liberty of our country on a permanent basis.” This combined with the Louisiana Purchase’s sheer popularity overcame any constitutional scruples. More important for Stearns’s argument, the purchase also ensured that “the newly created empire of liberty” would be commercial in character. After all, it confirmed the degree to which the geographical spread of America’s constitutional order was driven by trade and economic considerations. Over this free and commercial empire, Jackson would be elected president in 1828, almost forty years after swearing allegiance to a Spanish king.

High ideals have always gone together with economic self-interest in the history of the United States. Stearns’s achievement is to show just how much commercial dynamics drove the growth and unification of postrevolutionary America. Not for the first time, American politics and statesmanship turned out to be largely the handmaidens of trade and economic ambition.