American Expansionism

A nation’s need or desire for more territory is not unique to the United States. The colonies that created the nation were expansions into North American territory by England. However, domestic, foreign, and economic policy began to blend with the American ethos of manifest destiny in the first century of the United States. The result: nearly a century of American expansionism - the movement into new territories, sometimes by force, across the North American continent and other regions in the western hemisphere and around the globe.

American Expansionism: Definition and Background

After the American Revolutionary War and the Treaty of Paris in 1783, the United States gained all territory from England from the east coast to the Mississippi River. This is the first phase of American Expansionism. Americans could now move into the territory for cheaper land, including the Ohio River Valley. This land acquisition from the Treaty established several philosophies on the need for territorial expansion. One person in particular who was influenced was Thomas Jefferson. It reinforced his personal belief that the United States should focus on an agricultural economy. And for that to work, Americans needed fertile farmland available for the subsistence farmer.

Fig. 1 - This map from the United States Department of the Interior shows the expansion of American territory and the acquisition dates

The Beginnings of American Expansionism

The Treaty of Paris did not necessarily gain the United States territory it did not already have. As the American colonies were considered English claims, the Treaty gave all English claims in North America (excluding Canada and Quebec) to the United States. The first natural expansion of the United States occurred in 1803 with the Louisiana Purchase.

The Annexation of Florida (1819)

During the presidency of James Monroe, border disputes between the United States and Spain began to emerge along the southern border with New Spain (present-day Mexico). Secretary of State John Quincy Adams negotiated a treaty establishing a southern border with New Spain, the Adams-Onis Treaty. Before the treaty was negotiated in 1819, throughout the 1810s, the United States instigated several attacks on Seminole tribes in Spanish-controlled Florida. Spain reached out to Britain for assistance in stopping these incursions, but Britain refused. This put the United States in a favorable position when negotiating in 1819. Not only was a southern boundary established in the west, but Spain also ceded the Florida peninsula to the United States.

Fig. 3- This map shows the border created by the Adams-Onis Treaty and the lands ceded to the United States, including Florida

American Expansionism in the 1840s

The 1840s saw the next phase of rapid expansion of the territory of the United States: The Annexation of Texas in 1845, the acquisition of the Oregon Territory in 1846, and the cession of the southwest from Mexico in 1848.

The Annexation of Texas (1845)

Since the Adams-Onis Treaty in 1819, the territory of Texas was firmly in the hands of Spain and then Mexico after its independence from Spain in 1821. However, in 1836, Texas declared itself independent from Mexico and began petitioning the United States for statehood. The migration of American settlers into Texas fostered this independence movement. Mexico sent an army to quell the rebellion but was defeated by Sam Houston, and independence was granted.

What followed was nearly a decade of political issues and discourse over the statehood of Texas. The issue of Texas became a point of contention between the Whig Party which opposed the annexation, and the Democratic Party in favor. The main problem was slavery. In 1820, Congress passed the Missouri Compromise with great duress, establishing a boundary of which territories could have slaves and which could not. Northern Whigs feared Texas could create several slave states, upsetting the political balance in Congress.

Nevertheless, by 1845 the Democrats won out, and on his last full day in office, President John Tyler accepted the Texas annexation. His successor, President James K. Polk, upheld the annexation. Though the annexation was resolved, border disputes continued between the United States and Mexico, erupting in the Mexican American War in 1846.

The Oregon Treaty (1846)

After the War of 1812, Britain and the United States negotiated a northern border between British-held Canada and the United States along the 49-degree line of latitude to the Rocky Mountains. The region of the Rocky Mountains was jointly held by both nations, allowing for passage throughout.

Fig. 4- This map shows the region in dispute between Britain and the United States resolved by the Oregon Treaty

Over the decades, however, this deal became less attractive to both nations as the region's resources became more accessible and valuable. Negotiations began in the early 1840s, but Britain held firm to wanting the borderline to continue the 49-degree line. In contrast, American expansionists wanted a border farther north along the 54-degree line. The outbreak of the Mexican American War forced the Americans to fold on their demands as President Polk did not wish to have two wars at the same time. In June 1846, the U.S. and Britain signed the Oregon Treaty, establishing the northern border as the 49-degree line to the Pacific Ocean.

Mexican Cession of the Southwest (1848)

In 1848, The United States defeated the Mexican Army, and the Mexican American War ended. The Treaty of Guadalupe Hidalgo ended the war. In this treaty, Mexico ceded all claims to Texas, created a southern border along the Rio Grande, and Mexico gave up claims of Utah, Arizona, New Mexico, California, Nevada, and parts of Oklahoma, Colorado, Kansas, and Wyoming to the United States.

Manifest Destiny and Empire

Near the conclusion of the Mexican American War, the term Manifest Destiny is coined in the American news media. This term is used to define the growing American ideology that it is the destiny of the United States to control the territory of North America from the Atlantic to the Pacific. This ideology is bolstered by the rapid annexation and claims of territory, to the point that many Americans felt it was “God-given,” that if God did not want the United States to have this land, then the U.S. would have lost the Mexican American War, the War of 1812, and would not have allowed the successful negotiations of so many favorable treaties. Manifest Destiny would be a foundation for foreign policy until the twentieth century.

American Expansionism After the 1890s

The United States' territorial expansion in North America ended with the acquisition of Alaska. But it did not wholly end America’s desire for expansion. Guided by the Monroe Doctrine, the United States moved to claim territory in the Western Hemisphere to remove European powers from their sphere of influence and gain territory advantageous to American economic interests.

• Hawaii (1898): Since the 1880s, parts of Hawaii have been leased to the United States for military and economic purposes, such as Pearl Harbor. Over the next decade, several Anglo-Americans moved to the island nation. By 1893, tensions rose as an attempt to overthrow Hawaii's monarchy was attempted. The United States intervened, insisting their intervention was to protect the Americans on the islands. A provisional government was established with protests from the Hawaiian monarchy. But by 1895, the Queen of Hawaii abdicated, opening the path to annexation. President McKinley annexed Hawaii in July 1898.

• The Spanish American War (1898): In 1898, Spain began to intervene in the Cuban insurrection. Holding to the Monroe Doctrine, the United States invaded Cuba to remove the Spanish, starting the Spanish-American War. The war concluded with an American victory and the signing of the Treaty of Paris of 1898. In this treaty, Spain recognized the sovereignty of Cuba and ceded the territories of Puerto Rico, Guam, and the Philippines to the United States. These territories would remain under U.S. control, except the Philippines, which was granted independence in 1934. Guam and Puerto Rico remain U.S. territories.

Acts Against American Expansionism

Though expansionism and Manifest Destiny were the dominant ideologies for most Americans in the 1800s, some groups opposed the expansion.

• In the early years of expansionism in the 1840s, the Whig Party campaigned against expansionism as a means to combat the expansion of the institution of slavery.

• Many opponents of expansionism were against the treatment and destruction of indigenous peoples and societies that the United States controlled. Many tribes lost their homelands, were forced onto reservations or were destroyed entirely.

• Other opponents of expansionism in the 1890s were against the Monroe doctrine, who felt it was being used to instigate war rather than protecting American interests. Many had issues with the invasion of Cuba, seeing it as an unnecessary American intervention.