Continental Expansion

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Continental Expansion

David M. Pletcher

A special providence, some believe, has looked after the affairs of the United States through its history. If this is so, part of the concern has been geographical, for Americans have taken over more than one-third of North America, including much of its best landa broad swath stretching from sea to sea across almost twenty degrees of latitude.

Before the United States came into being, the three most powerful nations of the world in turn occupied most of this territory but had to give way eventually to the irresistible American advance. Some Americans were quite aware of what they called their destiny; at their independence, for example, Gouverneur Morris (as he later remembered) thought "that all North America must at length be annexed to ushappy, indeed, if the lust of dominion stop there." Fortunately, Morris's vision proved an exaggeration.

As the American nation grew, it worked out a flexible combination of expedience, usually legal or moral. To overcome each obstacle and obtain for it the land it wanted, the most direct method was negotiation followed by a treaty of some sort, providing for a land cession and certain benefits or safeguards for its inhabitants. On two occasions the negotiation followed a victorious war, once with Great Britain and once with Mexico. In the first the enemy grew tired of fighting and sued for peace; in the second, however, the Americans had to occupy the enemy's capital city and much of its country. On a third occasion, again involving Britain, the outcome was a draw and brought only minor boundary adjustments. On the fourth and last occasion, the United States resorted to purchasethis was the vast territory of Alaska.

The reasoning of Americans in acquiring their territory differed with the occasion. The first acquisition, specified in the Treaty of Paris of 1783 ending the revolutionary war, came with independence itself. For the other acquisitions the Americans worked out a flexible combination of expedients, usually legal or moral, to overcome each obstacle; they thereby obtained the land they wanted. The most direct was negotiation followed by a treaty of some sort, providing for a cession and certain benefits or safeguards for its inhabitants. Another expedient of territorial expansion was purchase, again involving a treaty that usually contained other provisions and sometimes followed hostilities. There also was a lot of sheer luckbeing at the right place at the right time. Behind the formalities of land transfer were such pressures as migration and trade that could bend or destroy boundary lines traced out on a map. The notorious mobility of Americans and their acquisitive instincts might thus defeat the plans of faraway Europeans. As Americans moved west across the continent these instincts were whetted by cultural contacts and reciprocal brutality between American settlers and their Native American neighbors and by prejudices against Spanish and French remembered from life in Europe and eventually against the mother country as well. As this developing American nationalism overcame the rivalry of individual colonies enough for cooperation during the Revolution and after, it inspired propaganda to reinforce expansionist instincts. While these factors encouraged expansionism in the New World, the international rivalries of the Old World claimed the attention and exhausted the resources of European rulers who would have liked to thwart the ambitious Yankees across the ocean if they could.


The Americans acquired their territory in four great expansions. The first of these resulted from the negotiation of peace following the revolutionary war. After the British surrender at Yorktown on 19 October 1781, talk of peace spread in Paris and London and informal exchanges began between representatives of both sides. (The Continental Congress in Philadelphia had been considering peace terms since 1779.) Talks stipulated the unqualified declaration of American independence as the first prerequisite and laid out extensive boundaries. While some members wanted to ask for all of Canada, the negotiating terms mentioned only the Ontario peninsula to the north, between Lakes Huron, Erie, and Ontario (the "Nipissing line") and territory around the Great Lakes as far west as the source of the Mississippi River. To the south, they optimistically included the eastern half of the Mississippi Valley down to 31 degrees, the northern limit of Spanish Florida and Louisiana. Cession of this lower valley was certain to be unacceptable to the ministers of France and especially Spain, who wanted to protect their nations' territory by shutting up the Americans east of the Appalachians. Agents of the two countries put pressure on Congress over the next two years with the result that by the Battle of Yorktown, instructions of June 1781 from Congress required the American peace commissioners to consult the French foreign minister, the Comte de Vergennes, on all matters except independence.

The Continental Congress named five commissioners to start negotiations, but only three played any active roles: Benjamin Franklin, John Adams, and John Jay, who were already in Europe seeking loans and other aid. They had good reason to suspect the motives of their European allies, especially Jay and Adams. They were also aware of more conciliatory feeling in some British circles, especially one minister who was rising to a leading position in the government. This was Lord Shelburne, who saw a chance to attract the Americans away from Vergennes, renew the formerly prosperous Anglo-American trade relations, and perhaps eventually restore some sort of imperial political connection.

The first half of 1782 was a time of rumor and confusion in both London and Paris. Shelburne became prime minister, but the British and French continued naval warfare in the Caribbean, and King George kept up his stubborn refusal to recognize the colonies' independence. The American commissioners concluded that it would be more rewarding to negotiate separately with Britain and avoid Vergennes's interference, although the alliance treaty specified a joint settlement. A breakthrough came when John Jay received what he thought was evidence that France and Spain intended to make a private agreement on boundaries in the Ohio Valley to restrain the Americans. Without informing Franklin, the most pro-French of the trio, Jay sent an agent to Shelburne to argue for a Mississippi River boundary and indicate that he and his colleagues would negotiate separately for preliminary terms. Franklin approved Jay's action, and so did Adams, who arrived in Paris several weeks later from his own mission in the Netherlands.

Negotiation of a preliminary treaty took place during October and November 1782. Jay wrote the basic draft, but Adams, Franklin, and the British negotiators made so many changes and argued so heatedly that each major historian has assigned a different set of credits for individual sections. Recognition of American independence caused little trouble, but Franklin, who had always wanted to annex as much of Canada as possible, had to give up the Ontario peninsula. In its place he accepted an irregular boundary along the midpoints of four Great Lakes and a series of rivers and lakes west to the source of the Mississippi River. Unfortunately, this line missed the river, creating a gap that was not closed until 1818. In the interim, the British retained theoretically the right to navigate the river. The boundary then ran down the Mississippi to 31 degrees and eastward along that line and a nearby parallel to the St. Marys River and the Atlantic Ocean. The Americans' greatest territorial gain was the eastern half of the Mississippi Valley, a true seat of empire. However, a secret article (largely written by Jay) offered Britain another line north of 31 degrees as an inducement to retain the Florida coast and peninsula instead of turning it over to Spain. With Canada still a British colony, this would have put America's Atlantic trade in a pincer and kept Florida indefinitely out of its hands. (Fortunately, Spain, failing to recover Gibraltar in Europe, demanded Florida in its place.)

The preliminary articles disposed of the most important boundary questions, so the remaining discussions dealt with other matters. The most important of these were the colonial debts owed to British creditors, the treatment of loyalists living in America or owning property there, and the New England fisheries, concerning which Adams played the dominant role. Since nearly all of western Europe had been involved in the war, the British had accounts to settle elsewhere. This sometimes worked to the advantage of the Americans by distracting the British from North American affairs or placing an extra premium on American friendship. The American commissioners were shrewd men of the world who took advantage of every opening offered them. (Adams and Jay were lawyers, Franklin a businessman and bureaucrat.)

During the two decades after the revolutionary war the major problems affecting U.S. foreign relations were commerce and western settlements. The British had recognized the irregular line along the Great Lakes as the northern boundary. However, even as the king signed the treaty, providing that the chain of border forts on American territory from Ogdensburg west to Mackinac should be evacuated "with all convenient speed," his home secretary was issuing an order saying in effect, "take your time." The cabinet in London was concerned about the future of the international fur trade and peaceful relations with the Indians north of the border, and it anticipated that the Americans would commit other treaty violations and thereby justify the retention of the forts. Not surprisingly, however, the suspicious Americans assumed that the British were trying to hold onto the West. In the early 1790s, when the British resumed fighting with the French, their violations of American neutrality reinforced the complaints of western settlers about British soldiers in the border forts and brought on a major crisis. In 1794, John Jay negotiated a treaty that averted a probably disastrous war by bringing about the evacuation of the forts and securing a few commercial concessions. For other reasons, Jay's treaty was highly unpopular and cost him his reputation, but it confirmed Americans' occupation of their northern frontier, especially since a victory over the Indians in northwest Ohio at the same time discredited the traditional allies of the British.

Just as important to the growth of the American West was its boundary on the lower Mississippi, into which all the valley's rivers drained, so that the entire trade of the area was funneled through New Orleans. When the Spanish took over control of the Gulf of Mexico coast from the British under the 1783 treaty, they tried to anticipate the flow of American settlers over the Appalachian Mountains by a number of defensive strategies. First, they encouraged the Indian nations of Georgia, Alabama, and Mississippi to form a buffer, but the development of trade with the Americans and the lack of Indian cohesiveness frustrated this effort. In the late 1780s they sent an emissary to persuade the American government to give up its efforts to open the lower Mississippi to trade in return for concessions to Americans trading across the Atlantic. However, the southern states (which had no large seaports but many western connections) formed a solid bloc in opposition. Finally, the Spanish government intrigued western leaders to secede and become a Spanish protectorate. A few, such as James Wilkinson, nibbled at the bait, but by this time the Constitutional Convention of 1787 fore-shadowed a new government, strong enough to defend American interests in the West, and the Spanish efforts died out.

Although the Spanish could not prevent the migration of American settlers into the eastern Mississippi Valley, they denied them the right to ship their goods downriver to New Orleans and built several forts on the east bank, which they claimed as far north as the junction with the Ohio. The Americans, who held title to the east bank only from the British, had to wait and watch while Spanish politics moved languidly to and fro according to the progress of the French Revolution, then in its radical phase. From 1793 to 1795, Spain was actually an ally of its old enemy Britain against the Jacobins. In 1795 the Spanish withdrew from the war and indicated that they were ready to negotiate with the Americansperhaps because they were nervous about the significance of the recent American Jay's Treaty with the British or because they had abandoned hope of stopping their westward migration. (Historians are still unsure.) The result was Pinckney's Treaty (1795), which was so popular that the Senate approved it unanimously. In it Spain recognized the 31-degree boundary and agreed to evacuate its forts (although this took two years). It also granted the Americans the right to navigate the lower Mississippi and warehouse their goods on shore while awaiting ocean shipment (the "right of deposit").

Like Jay's Treaty, Pinckney's Treaty confirmed an earlier expansion by giving the United States control over its borders. As Americans poured into the new states of Kentucky, Tennessee, and Ohio, they shipped their products down the Mississippi to New Orleans and out into the Gulf of Mexico and the ocean to the east coast and Europe. American attention turned again to the Atlantic world, and the United States fought a brief naval war with France over neutral rights, which formally ended the alliance between the two countries but did no serious damage to either one. A new leader in France, Napoleon Bonaparte, won victories over most of western Europe and signed a temporary truce with Britain.


The short-lived stability in Europe was the background for the second great continental expansion gained by the American Republic. Napoleon, seeking new worlds to conquer, looked to North America and considered an economic empire on the British model, based on trade: Caribbean sugar to Europe, French manufactured goods to French settlers in temperate Louisiana, and temperate climate foodstuffs to the Caribbean to feed the slave labor there. It was at best a risky scheme, for a slave revolt had been raging in Santo Domingo, the principal French sugar island; Americans were pressing across the eastern Mississippi Valley; and French factories were not yet prepared to supply colonial demands. Most important, the French navy was too weak to defend this ambitious trade against the jealous British. Nevertheless, Napoleon persuaded Spain to exchange Louisiana for the Italian province of Tuscany (intended for the king of Spain's brother-in-law) and prepared an army for Santo Domingo.

When the new American president, Thomas Jefferson, learned about the secret retrocession of Louisiana, he instructed the U.S. minister to France, Robert Livingston, that he must bring Napoleon to sell the city of New Orleans to the United States. "[From] the day that France takes possession of New Orleans," Jefferson declared, "we must marry ourselves to the British fleet and nation." Livingston spent most of 1802 trying to convince Napoleon of the worthlessness of Louisiana without the Florida coast (which Spain refused to give up) and the near-certainty of friction with the United States. After several months of this deadlock, the Spanish government, which, with characteristic delay, had not yet carried out the retrocession, withdrew the right of deposit in New Orleansfor reasons about which historians are still uncertain. The American westerners, seeing their flourishing New Orleans trade thus abruptly cut off, flared up in protest, calling for action, and the Federalist Party, now out of power, began to demand a renewal of the war with France and the seizure of New Orleans. To gain time, Jefferson sent James Monroe, a well-known Virginian who was popular both in the west and in France, to join Livingston. During the three months between Monroe's appointment and his arrival in Paris, Napoleon impulsively decided to sell to the Americans not only New Orleans but the entire province of Louisiana, comprising the western half of the Mississippi Valley. As reconstructed by historians, the reasons for this momentous decision constitute one of the classic historic cases of multiple causation. In the first place, Napoleon's plan for an economic-based empire was falling apart. The conquest of Santo Domingo, the hub of the project, was going badly; yellow fever had decimated the French troops, and in November General Leclerc died of the disease. Napoleon had to send his successor troops that he had intended for the takeover of Louisiana from the Spanish. Those that remained were held in a Dutch port by an unusually hard winter. From his minister in the United States, Napoleon was learning of the American upheaval over the right of deposit, more serous than he had first thought. Finally, and perhaps decisive, tension in Britain and on the Continent suggested that the stalled war was about to break out again. Napoleon was beginning to turn his attention to possible hostilities in Europe, for which he would need funds.

Monroe and Livingston negotiated the terms of the purchase together, although each later tried to claim principal credit for the deal. The French asked 100 million francs at first but settled for 60 million ($11,350,000). The Americans, not having cash, arranged to pay in bonds at 6 percent. In addition, the United States assumed $3,750,000 of French citizens' claims, making the total purchase price about $15 million. The negotiations were hurried through in less than a month to fore-stall the outbreak of war or any interruption by Britain or Spain. The boundary of Louisiana was loosely drawn, but it clearly did not include East or West Florida or Texas, as some Americans later argued. Jefferson welcomed the news (which he had partly anticipated), although he was embarrassed by the doubtful constitutionality of the act. At first, he thought a constitutional amendment would be required, but he quickly dropped this scruple for fear that the providential deal might fall through at the last minute. Most of the Federalists held their peace too after a little grumbling.

The aftermath of the Louisiana Purchase was an anticlimax that took some of the bloom off Jefferson's successful first administration. After the negotiations were over, both Livingston and Monroe decided that the Louisiana Purchase included East and West Florida (that is, the peninsula and the Gulf coast to the Mississippi). On Jefferson's instructions, they put pressure on both Napoleon and the Spanish government with no success. Unwilling to go to war, Jefferson reconciled himself to a waiting game and got Congress to set up Mobile Bay as a customs district and later to appropriate $2 million to have on hand in case of an unexpected opportunity. The sorriest development of the whole period was the Burr Conspiracy (18041806), in which Aaron Burr, an outcast after his duel with Alexander Hamilton, exploited western unrest to concoct what was either a secessionist intrigue or a filibuster plot aimed at Texas and Mexico.

Madison, less patient than Jefferson, resorted to covert force and guile. When the inhabitants of the Baton Rouge area grew restive under Spanish rule, he sent an agent to tell them that the United States would welcome a revolution and warned off the British, whereupon the inhabitants seized the feeble Spanish fort. The rest of West Florida and part of East Florida fell to George Mathews, a revolutionary war veteran who led a force of "patriots" across the border. When Madison's opponents attacked the illegality of the act, he repudiated his agent, much to Mathews's disgust.

Following the War of 1812, the Monroe administration reverted to diplomacy to complete the acquisition of Florida. But force and the threat of force were not wholly absent from the process. After peace returned, General Andrew Jackson, commander of the military district on the southern border, broadly interpreted his vague orders and led troops into East Florida to fight Indians and protect border settlers. In the process, he captured several Spanish forts and executed two British army officers who, he said, were inciting the Indians against the Americans. Spain protested but realized that it might lose Florida anyway without action and agreed to treaty negotiations, especially after Secretary of State John Quincy Adams answered the protest with an aggressive reply, "a great gun from Washington to Madrid," as Adams's nephew pronounced it. (The British also protested but then dropped the matter.) The treaty was mainly devoted to the west boundary of the Louisiana Purchase, which was drawn on a zigzag line from the Sabine River on the modern Louisiana-Texas border to the modern north border of California (42 degrees). Many nationalists, especially southerners, resented the relinquishment of the slight American claim to Texas, but thereby the United States gained the equally weak Spanish claim to the Pacific coast, which helped to redirect American political power toward the West.

The War of 1812 gained no new territory for the United States, but it was important for avoiding the loss of land to the north and northwest. The United States went to war proclaiming, "On to Canada!" and hoping to acquire the Ontario peninsula at last. The British, for their part, hoped to set up an Indian protectorate between the Great Lakes and the Ohio River, both to halt the American westward movement and to create trade. They also planned sizable boundary adjustments in New England, New York, and the Northwest. By 1814 the ambitions had shrunk so far that the negotiations produced a status quo ante peace. This was quite enough for the Americans, who received it with relief as a renewed guaranty of their independence.

Two postwar agreements, each having the effect of a treaty, refined and strengthened the original treaty of 1783 fixing the northern boundary of the United States. The Rush-Bagot Agreement of 1817 limited naval armament on the Great Lakes. The Convention of 1818 drew the northern boundary along the parallel of 49 degrees from the Lake of the Woods to the "stony mountains" and provided that the territory from the mountains to the Pacific coast should be occupied by British and Americans without injury to claims of either country (generally called "joint occupation"). The convention was to last ten years, renewable until denounced. It also ended two vestiges of the past, the "boundary gap" of 1783 and the much-argued British right of navigation on the Mississippi.

A large boundary gap had existed since 1783 at the eastern end of the north border, from the point where the forty-fifth parallel crosses the St. Lawrence River to that where the St. Croix River enters the Bay of Fundy (comprising the modern north borders of New York, Vermont, New Hampshire, and Maine). Local inhabitants disagreed as to which of several rivers was "the true St. Croix." Afterward, a trail of boundary commissions, documents, and maps led from the Peace of Paris to the Treaty of Ghent without any definition of "the North West Angle of Nova Scotia," the "north-western-most head" of the Connecticut River, and other place names on the outdated Mitchell map of 1755. The War of 1812 gave new importance to the boundary controversy, for it convinced the British that they needed a military road between Quebec and Halifax.

The admission to the union of the state of Maine in 1820 also complicated the question, because Massachusetts still had land claims in the disputed area, so now there were two sets of governors, legislatures, newspapers, and citizenry squabbling over geographical details, to say nothing of the federal government in the national system. Two efforts after 1815 to settle the question added further problems, because a boundary commission discovered that an expensive American fort at Rouse's Point had been built on Canadian soil through a surveying error. Also, a boundary line drawn by an arbiter, the king of the Netherlands, did not satisfy many Americans, who accused him of pro-British bias. The nationalist Andrew Jackson, however, thought the dispute had gone on long enough and tried in vain to get the king's award accepted.

It took a major Anglo-American crisis to bring about a solution to the Maine boundary problem. In 1837 a double revolution for self-government in Ontario and Quebec drew in hotheaded sympathizers and covetous expansionists from upper New York State, eager to strike a blow for freedom and mount a filibuster at the same time. A land war broke out in northern Maine when frontiersmen from both sides of the line discovered the Aroostook Valley, a pocket of fertile land, and started to fight over it. The commanding general of the American army, Winfield Scott, was sent to intervene and restore peace, and Britain appointed a diplomat, Lord Ashburton, to negotiate a settlement. He and Secretary of State Daniel Webster (who happened to be his personal friend) managed to draw a compromise line with information from sixty-year-old maps. By a curious anomaly, each side possessed information supporting the other side's case. Webster showed his maps to the Maine politicians to silence their objections; whether he also used money supplied by Ashburton has fascinated and baffled everyone who has written on the subject. In any case, it seems likely that Webster's attentions made a peaceful outcome possible but lost the United States about five thousand square miles of Maine woods and swamps. Smaller adjustments were made to the west in New Hampshire and Vermont, and the United States gained a sliver of land in New York, including "Fort Blunder" on Rouse's Point. More important was a cession of about six thousand square miles in Minnesota that proved later to contain some of that state's invaluable iron ore deposits.

The Monroe Doctrine, enunciated in the president's annual message of December 1823, did not contribute directly to continental expansion, for much of it applied to Central and South America. However, one part of it, the noncolonization principle, foreshadowed the annexation of Alaska forty-four years later. In 1821 the czar of Russia, seeking to expand his control over his far-away colony, issued a ukase claiming its boundary to 51 degrees north latitude and forbidding non-Russian ships to come within one hundred miles of this coast. When a burst of protest from New England farming and fishing interests followed, Secretary of State John Quincy Adams, their perennial champion, got Monroe to announce in his message that the Western Hemisphere was no longer open to European colonization. By implication Adams intended his warning for Britain as well as Russia. It had no basis for legality in international law, but the czar never enforced his ukase. In a treaty of 1824 Russia fixed the southern boundary of its colony at 54 degrees, 40 minutesthe "fifty-four forty" of a later American political slogan.


The next great continental expansion of the United States comprised the entire western third of the lower forty-eight states, from the west boundary of the Louisiana Purchase to the Pacific Ocean. It was accomplished in only five years, from 1843 to 1848, but it was foreshadowed and prepared for by several migrations of American people, the spontaneous formation of governments on the American model, and the spread of an infectious propaganda resting on the brash assumption that American absorption of the desired territory was inevitablethat the Almighty had destined the territory for His "chosen people" as a kind of divine favoritism. This idea, like so many others in American colonialism, was inherited from the mother country. In the sixteenth century, the writings of Richard Hakluyt and others set forth the idea that, like the earlier Romans, Englishmen were preordained to take over, colonize, and develop the New World; no other people were capable of such a gigantic task. Destiny could be used just as easily to support American independence as to rationalize British imperial expansion, and revolutionary thought in the colonies was filled with echoes of the "city on a hill" and the "American Israel" blessed by Providence. Thomas Paine's statement in Common Sense that the Americans were fighting "the cause of all mankind" was only the most famous of many such declarations.

This potent propaganda, together with migration, American-style government, and an overall sense of an inevitability went to work in Texas during the 1820s. Texas had been a province on the north border of New Spain. When Mexico took over in 1821, its leaders thought to replicate the prosperous growth of the United States by encouraging the migration of American settlers as models into sparsely populated Texas, despite the warnings of a few prescient critics that this would amount to "settling the Goths at the gates of Rome." Americans, mostly Protestants speaking only English, gladly settled on the fertile cotton bottoms of east Texas and brought their slaves with them. (Mexico was officially Roman Catholic and Spanish speaking, and its constitution declared all men equal.) The new American population established commercial ties with New Orleans, since the nearest Mexican centers lay far to the south, and the people of central Mexico had little interest in Texan affairs, being much involved in their own political struggles. Frictions led to quarrels, and despite the efforts of a few Texan leaders to patch up disputes, the province revolted for independence in 1836. The Mexican president, Antonio López de Santa Anna led an army north to crush the rebels into submission, only to blunder into defeat at the Battle of San Jacinto in east Texas. Santa Anna was captured and forced to sign a treaty recognizing Texan independence.

Evidence of overt U.S. participation in the Texan revolution is slim. President Andrew Jackson's public behavior was correct, but the Texan general, Sam Houston, was his friend, and he followed the military action with keen interest. The American people, especially in the lower Mississippi Valley, were very sympathetic and contributed money and supplies freely; frontiersmen flocked into the Texan forces. An American general, Edmund P. Gaines, led a few troops fifty miles across the border but contributed nothing to Texan success. Not surprisingly, some Mexican nationalists have always believed that U.S. intervention gave the Texans their victory, and a small plot thesis has grown up among American historians, but their evidence is shallow.

Most of the victorious Texans hoped for prompt incorporation into the American Union, but this proved impossible because the United States was then implacably divided over the question of adding slave territory. In Europe, Britain and France opposed letting the United States strengthen itself through annexation. The British wanted an assured supply of cotton for their mills, and some inconsistently supported Texan abolitionism, as well. These contrary forces produced nine years (18361845) of frustrating diplomacy, while the ramshackle republic of Texas maintained a precarious existence, its government housed in log cabins on the western frontier, and a weak American president, John Tyler, tried to put together an annexation coalition to ensure his reelection.

In 1844, Tyler managed to sign an annexation treaty with Texas, only to see it defeated in the American Senate, partly because it came to a vote in the midst of a hard-fought presidential election campaign. The victor was an expansionist Democrat, James K. Polk. He favored annexing Texas, but Tyler tried to anticipate him during the three months he had left in office. In his hurry, he used an untried method, a joint resolution in both houses of Congress. At the same time, a diehard British agent in Mexico made a last-minute effort to secure that country's recognition of Texan independence. His failure and the Texan acceptance of terms offered by the joint resolution brought the annexation question to a dramatic conclusion.

On the Pacific coast the process of annexing California and Oregon was going on while that in Texas was drawing to a close. After Mexico won its independence it neglected its distant border provinces, and in the early 1830s American merchants established trading posts along the coast at Monterey, California, and a few other small ports, which became centers of American influence. At Monterey, Thomas O. Larkin, the most important merchant, became a U.S. consul and an important source of information about conditions in California. By the 1840s these merchants were joined by American explorers, hunters, and trappers crossing the mountains. They soon developed another center of American influence at a backwoods fort near modern Sacramento built by John A. Sutter, a German Swiss, who obtained a Mexican land grant in 1840 and founded a polyglot settlement. The Hudson's Bay Company, moving southward from western Canada, formed the third corner of the triangle competing for influence in California. The Mexican government maintained loose control over these disparate elements with little or no supervision from Mexico City. Americans on the East Coast exaggerated the European, especially the British, threat to California, and even Anglophile Daniel Webster tried to include in his negotiations with Ashburton some provision for the transfer of the San Francisco Bay area to no avail. The degree of American nervousness about California was shown by Thomas Catesby Jones, commanding the U.S. Pacific Squadron. In 1842, hearing a false rumor of an Anglo-American war, he took it upon himself to seize the port of Monterey, only to have to back out in an atmosphere of general embarrassment.

To the north of California, Americans were also much interested in the vaguely defined Oregon Territory, which the United States had occupied jointly with Britain since the northern boundary settlement at 49 degrees (1818). The British, who had explored and mapped the area as far as the Alaska border, had a better claim to it, but an American ship captain had discovered the mouth of the Columbia River, and the Lewis and Clark expedition (18041806) had explored the Columbia and Snake River valleys. Five years later, John Jacob Astor established a fur trading post and fort at Astoria, near the mouth of the Columbia, and in the Florida treaty of 1819 the United States acquired the Spanish claim south of the river. After that time, the Oregon question largely revolved around the triangle of land north of the Columbia River (modern Washington State), especially the coasts of Puget Sound, with their excellent harbors.

For the time being the British established monopoly control over the Columbia Valley through their fur trade and agriculture, and they even furnished food for the Russian settlements in Alaska. Meanwhile, the Americans, led by westerners in the House of Representatives, tried to alert their countrymen to the danger that Britain might forestall them in Oregon. In 1827 the two nations reviewed the whole question. The United States offered to extend the 49-degree line (established in 1818) and cede all of Vancouver Island to Britain (the eventual settlement); Britain offered only several ports on the Olympic peninsula, which its navy could easily take over in wartime. The joint occupation continued, and the Hudson's Bay Company remained the de facto ruling power in Oregon. To the disappointment of both governments, Webster and Ashburton decided not to included Oregon in their negotiations.

At this point the tide began to turn. A new British treaty with China raised trade possibilities in Asia, and British colonies in New Zealand and elsewhere began to compete for settlers with Puget Sound; also, the Hudson's Bay Company's interest in the lower Columbia valley began to cool. At the same time American concern over Oregon increased, and a new burst of speeches and memorials forced the issue on the public. Missionaries were sent out to work among the Oregon Indians, and their enthusiastic reports on the beauties of the country stimulated the migration of families and sometimes whole communities to Oregon. A trail of sorts had existed as early as the War of 1812, and by the 1830s it was an institutionup the Platte River, across the prairies and mountains, through South Pass, down the Snake River, and finally to the Columbia. (At Fort Hall an alternate route led into California.) Many travelers went as far as a tributary of the Columbia, the Willamette, whose banks resembled parts of the Middle West so much that it became a common goal. The climax of the migration came in 1843 as returning prosperity made possible improvements in equipment and supplies. To many observers it seemed that time was working for the Americans, and a group of Southern Democrats led by John C. Calhoun spoke out for "a wise and masterly inactivity." At that point Calhoun became Tyler's secretary of state. Since Britain had about concluded that the 49-degree line was the best it could obtain at that time, preliminary negotiations began between Calhoun and the British minister, but these became hung up on details, and soon the presidential election of 1844 intervened. In the campaign, western activists kept alive their demand for all of Oregon up to the boundary of Russian Alaskaa grant of land altogether unjustified by circumstances and likely to cause war with Britain.

The new president, Polk, brought about a wholly unnecessary crisis with Britain as he maneuvered to keep together the two factions of his party, the activists (western) and the pacifists (southern, led by Calhoun). First he took advantage of a British misstep to close off Tyler's negotiations, in which he thought the American position was too weak. Then he referred the whole question to Congress, so the western fulminations could alarm the British. It was at this point, and not earlier, that the slogan "Fifty-four forty or fight" spread across the country. After a heated debate, Congress voted to send Britain a mild, unthreatening notice abrogating the joint occupation. The British took the initiative, as Polk had intended, and the diplomats quickly settled on the forty-ninth parallel, awarding all of Vancouver Island to Britain. The British gave up the right to navigate the lower Columbia, avoiding possible commercial friction in the future. Thus, Polk carried off his policy through rigid party discipline but he risked a costly war for purely partisan gains.

American migration into California during the early 1840s, though smaller than that into Oregon, continued to tip California toward the United States, thanks especially to the publicity given to the SacramentoSan Joaquin area by the well-known explorer John Charles Frémont, whose report on his two expeditions was a bestseller. In September 1844 a group of native Californians with some Americans overturned the local Mexican governor and set up their own virtually autonomous government. When Polk took office in March 1848, he intended to negotiate for California, and the War Department sent Frémont back into the province. The British also dispatched a warship to visit the north Pacific and be on hand in case of a local revolt. For its part, the Mexican government gathered several hundred soldiers as reinforcements for California, but on their way to the West Coast they encountered a local uprising and joined it, bag and baggage.

As the Texas question wound down in 1845, Polk set his Mexican policy in motion. It was both aggressive and defensive at the same timeto mount a strong front, assume the benefit of every doubt, and challenge every assumption of his opponent, while avoiding any overt act that might commit him beyond recalla policy of bluff, indeed, but bluff with an avenue of retreat. Since Mexico had broken relations with the United States over the annexation of Texas, Polk sent an envoy to start negotiations, although by usual practice Mexico should have acted first. The envoy, John Slidell, was chosen largely for his fluency in Spanish. Polk instructed him to offer $5 million for the cession of Texas to the Rio Grande and New Mexico and $25 million for California, including San Francisco and Monterey. The president indicated later that Slidell might bargain beyond the figure for California but he made no mention of an explanation or indemnity for the already completed annexation of Texas. Even before Polk drew up these instructions for Slidell, he took care that his envoy should negotiate from a position of strength by stationing troops under General Zachary Taylor at Corpus Christi in southeast Texas.

In early October news arrived from Polk's agent in California, the merchant Thomas O. Larkin, that forced Polk to hurry his plans. Larkin described British and Mexican activities that seemed to point to a British seizure of the province. It is now known that Larkin's information, five months old, was based on rumor and entirely false, but it must have deeply shocked Polk and his cabinet. He sent off new instructions to Taylor, Larkin, and the commander of the Pacific Squadron, John D. Sloat. Taylor was to advance to the Rio Grande (the farthest line claimed by Texas). Sloat was to conciliate the Californians, keep his ships ready for further orders, and, if war broke out, seize the principal California ports; he was also reinforced. Larkin became confidential agent to report on developments and defeat any foreign efforts to control California. Separate orders were sent to Frémont in California. No one has discovered what these orders were or in particular how much freedom they gave to a notoriously flighty man of action.

Having set out his lines, Polk now had to wait to see their effect, while Congress plunged into debate over Oregon. Slidell arrived in Mexico at the beginning of December to find that the president, who favored negotiating but was only clinging to power, would not receive him. A new regime, more nationalistic and stubborn, soon took power, and Slidell resigned himself to waiting outside Mexico City and reporting on the situation. Meanwhile, General Taylor and his troops were marching to the Rio Grande, which they reached in March. They built a temporary fort across the river from the Mexican town of Matamoros (modern Brownsville, Texas). The Mexicans responded by sending a reconnaissance party across the river. On 25 April this force clashed with an American scouting party, took some prisoners, and shed the first blood of the war. At the same time, Polk recalled Slidell and he and news of hostilities on the Rio Grande arrived in Washington at the same time. On a Sunday morning, Polk, glad to have some justification for acting, called his cabinet together and drew up a war message. In this he branded the Mexicans as the aggressors and the conflict as a defensive one, "war by the act of Mexico." Polk's enemies in Congress, the Whigs and Calhoun, would not accept this, but Polk's Democrats introduced appropriation bills and other measures to support the troops, and presently patriotism blurred the distinctions, and a formal declaration of defensive war crept through. (Mexico too declared a defensive war.)

When the American cabinet discussed the goals of the war, the cautious James Buchanan (secretary of state) proposed a circular letter disavowing any territorial ambitions beyond the Rio Grande boundary for fear of a British or French intervention. Polk firmly vetoed such a statement. By the end of May he had decided on the annexation of all Upper California, New Mexico, and perhaps other parts of northern Mexico. As soon as Congress passed the war bill, Polk ordered a blockade of the California coast and sent General Stephen W. Kearny, then in Missouri, to lead troops westwardeventually to occupy California. Taylor's initial victories over Mexico (Palo Alto and Resaca de la Palma), as well as the settlement of the Oregon question, reduced the danger of British intervention in California. During June, before the news of war reached the west coast, Frémont touched off a revolt against the local authorities and captured the town of Sonomawhether on instructions from Washington, no one knows for certain. Commodore Sloat after some hesitation proclaimed American rule. (Actual conquest, however, would await the arrival of General Kearny and his regular troops.) Events in the principal theater of war had less connection with continental expansion. Taylor pressed southward through Matamoros, Camargo, Monterrey, and Saltillo, but a fierce battle at Buena Vista in February 1847 convinced Polk that the army had reached a dead end. He created a second army, commanded by Winfield Scott, which landed at and captured Veracruz, then pushed into the interior of the country toward Mexico City. Reaching the central valley of Mexico, Scott finally occupied the capital in September 1847.

Polk had not originally intended to go so far. He expected a short war, having no idea of the Mexican sense of honor or stubbornness. So the war became a series of advances followed by pauses in which action was stopped to see if the Mexicans would yield. During one of these pauses, after Scott had occupied Veracruz, Polk appointed Nicholas Trist to join Scott as a commissioner and be ready to act as soon as the Mexican showed any interest in negotiating. (Trist was a minor official in the State Department. Polk did not care to send the elderly Buchanan so far away.) After the American capture of Mexico City, the Mexican government, by now controlled by moderates, retreated to an interior town. An important force working for peace was the British legation, because after the fall of Veracruz, the British government had resigned itself to an American victory and was now anxious to end the war as quickly and cheaply as possible. Trist, Scott, and Mexican representatives with British advisers discussed terms in Mexico City, and a man on horseback carried these to the Mexican government a hundred miles away for further discussion. Polk played no active role in the negotiation of terms, and, indeed, was so disgusted with the proceedings that at one point he ordered Trist to stop negotiating and come home. Fortunately, Trist disobeyed; for this, the vindictive president stopped his pay (Congress made an appropriation twenty-two years later.)

The treaty so torturously produced kept surprisingly close to Polk's early idea of the war's goals. It ceded to the United States all of Upper California and New Mexico and drew the U.S.Mexico boundary at the Rio Grande and Gila Rivers. In return the United States was to pay $15 million and assume $3.25 million of American claims against Mexico. The cessions did not include Lower California or the Isthmus of Tehuantepec, which had been mentioned as a transit route for a railroad or canal, but the United States had not occupied these territories, and annexing them at that time would have presented serious problems. Considering the sectional rivalries the country faced, it had taken perhaps too much as it was. During the last months of the war, a movement grew in the United States to annex all of Mexico as the only way to reimburse the nation for the expense of the war. In addition, among the divided Mexican parties one left-wing group favored an American protectorate as the only way of pushing through changes such as clerical reform, which Mexico badly needed but could not manage by itself.

When Polk saw the treaty signed by his disobedient agent, he was furiously disgusted, but he swallowed his rage and transmitted the document to the Senate with minor changes. A coalition of extremists who wanted to annex more of Mexico and who wanted a peace without annexations threatened to defeat the treaty and throw the negotiations open again. Proceedings were delayed by the sudden death of John Quincy Adams in the House chamber and this may have provided time for common sense to prevail. Eventually, moderates gathered themselves together and approved the Treaty of Guadalupe Hidalgo with Polk's amendments by a vote of 38 to 14.


But the treaty did not complete American border expansion to the southwest. In the first place, the Treaty of Guadalupe Hidalgo, like the one after the American Revolution, was based on an inaccurate prewar map, so a boundary commission had to run the whole line on the ground, a process causing new quarrels with Mexican state and federal governments. Second, Mexicans complained that Indians north of the new border were increasing their raids into Mexico. They demanded that the United States carry out Article 11 of the peace treaty, requiring it to restrain the border Indians from raidingan impossibility with the available infantry troops. Third, American filibusters crossed the border almost at will, seeking to detach Mexican states and complete the absorption process begun by the war. Fourth, American railroad interests discovered belatedly that the best route for a southern transcontinental railroad lay south of the Gila River in Mexican territory. Finally the question of rail transit across the Isthmus of Tehuantepec, omitted from the peace treaty, was taken up by the commercially minded Taylor-Filmore administration, as Americans acquired interests in transit concessions.

All of these considerations figured in the effort of the Franklin Pierce administration to acquire more land from Mexico. Pierce appointed the railroad owner James Gadsden minister to Mexico and gave him a list of desired territories and corresponding prices to be offered. The maximum price was for Lower California and a good part of northern Mexico, the minimum for a strip of territory south of the Gila River big enough for the contemplated transcontinental railroad.

In Mexico, Gadsden's negotiating partner was Antonio López de Santa Anna, the opponent of the Americans through the Texas question and the Mexican War. Santa Anna was as eager as ever for money but wary of nationalist opposition to more land grants. Gadsden was a bumbling diplomat given to grandiloquent and imprecise language. Other complications were efforts by another agent from Pierce to insert the Tehuantepec question and a filibuster expedition to Lower California by the notorious guerrilla leader William Walker. Santa Anna, now desperate, put out feelers for British or French aid to no avail. In the end, he gave up a thin triangle of land south of the Gila large enough for a railroad and released the United States from Article 11 of the peace treaty. For this minimal grant, the United States agreed to pay $15 million plus $5 million for private American claims. The Senate was in the midst of a furious debate over the Kansas-Nebraska Act but took up the Gadsden treaty, too. It lowered the purchase price to $10 million and somewhat increased the land area acquired. Outside the continent, it opened the Isthmus of Tehuantepec to American transit, but it did not give the United States access to the Gulf of California, as some had hoped.


The fourth and final great continental expansion that produced the present-day continental proportions of the United States was the purchase of Alaska from Russia in 1867. From the late eighteenth century, both Russia and America had sought out the northwest coast of North America for furs, mostly of sea otters and seals; Americans also pushed the whaling industry into the north Pacific. After the United States acquired California in 1848, San Francisco became the center of trading companies and other enterprises extending their activities northward. The most striking of these expansionist ventures was Perry Macdonough Collins's project to extend a telegraph line across western Canada, Alaska, and the Bering Strait to Siberia, where it would connect with Russian and other European lines. (Unfortunately, it could not compete with Cyrus Field's transatlantic cable for investment funds.)

American public interest in acquiring Alaska had already been rumored occasionally. At the time of the Crimean War, some Americans were considering taking over Russian holdings in the Alaska panhandle to keep them out of British hands, but the British avoided this action by agreeing to neutralize Russian property there. Even before then, a few American expansionists, especially William H. Seward, a Whig senator from New York, were attracted to Alaska. Seward regarded it as the key to an expanded Pacific commercialism pointed toward the Far East, especially China, which had long been a magnet for expansionist American businesspeople. At this time, Russia was losing interest in its remote, unprofitable colony. Fearful that the United States or Britain would take it over without paying for it, the czar and his government decided on the sale to the Americans. As secretary of state, Seward eagerly received the Russian overtures, and he and the Russian minister to the United States drew up a treaty literally overnight. The American public and press were taken by surprise and Seward and his fellow expansionists had to put together an intensive lobbying campaign to sell the treaty to Congress. The United States paid $7.2 million to Russia, and historians feel that perhaps $200,000 of that went to congressmen in one way or another to buy their votes for the bill appropriating the purchase price. (Perhaps many would have voted for it anyway.) Not for the first time in American history, expansionism was temporarily discredited, and later efforts to purchase the Danish West Indies and the Dominican Republic were voted down amid accusations of scandal. Nevertheless, the United States promptly set up a government in Alaska, and American business promoters started to take over Russian enterprises.

After the Civil War, the United States was unable to extend is borders northward into Canada. During the late 1860s, annexationism raised its head in British Columbia and Manitoba and then fell back. In the first case, Seward tried to encourage the discontented British Columbians, and in the second case, a group of New York and Minnesota railroadmen and other business interests tried to exploit a local rebellion early in the administration of Ulysses S. Grant. At an earlier date either case might have led to further continental expansion, but at this time, all the Americans could achieve was an arbitral award of the San Juan Islands by the German emperor in 1871. (These islands, left in dispute by a vague passage in the Oregon Treaty of 1846, were strategically located in the channel just off Vancouver Island.)


Why did American continental expansion come to such an abrupt halt after the Alaska purchase? Perhaps the unsavory rumors of corruption were responsible but bickering and carping had not lessened American ardor for long after the Louisiana Purchase or the Mexican War. More likely, the formerly irresistible American expansionist impulse encountered a powerful counterforce, for in 1867, only three months after the annexation of Alaska, the Canadians formed a self-governing dominion, and soon afterward, the regime of the first prime minister, Sir John Macdonald, began construction of a transcontinental railroad that would bind the dissident provinces such as British Columbia and Manitoba to the nation. Probably also American businessmen came to realize that economic ties could be as valuable to them as political control over a people who, like the Americans themselves, wanted to be independent.


Bemis, Samuel Flagg. The Diplomacy of the American Revolution. New York, 1935. Old but especially good for boundary settlement.

. John Quincy Adams and the Foundations of American Foreign Policy. New York, 1949. Solid accounts of several episodes from 1815 to 1830.

DeConde, Alexander. This Affair of Louisiana. Baton Rouge, La., 1976. One of several good accounts.

Garber, Paul Neff. The Gadsden Treaty. Philadelphia, 1923. An old work but still useful.

Jensen, Ronald J. The Alaska Purchase and Russian-American Relations. Seattle, Wash., 1975. More detail on the treaty negotiations.

Jones, Howard. To the Webster-Ashburton Treaty. Chapel Hill, N.C., 1977.

Merk, Frederick. Manifest Destiny and Mission in American History: A Reinterpretation. New York, 1963. A minority view of manifest destiny and events of the 1840s. Should be compared to Weinberg.

Morris, Richard B. The Peacemakers: The Great Powers and American Independence. New York, 1965. More detailed scholarship.

Pletcher, David M. The Diplomacy of Annexation: Texas, Oregon, and the Mexican War. Columbia, Mo., 1973.

Saul, Norman E. Distant Friends: The United States and Russia, 17631967. Lawrence, Kans., 1991. Cross-archival study of a complex relationship.

Stuart, Reginald C. United States Expansionism and British North America, 17751871. Chapel Hill, N.C., 1988. Covers the whole span of continental expansion.

Weinberg, Albert K. Manifest Destiny: A Study of Nationalist Expansion in American History. Chicago, 1935. Still the standard work on the subject.

See also Colonialism and Neocolonialism; Imperialism; Nationalism .

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