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The Pre-Civil War Era (1815–1850)

History SparkNotes

Manifest Destiny: 1835–1850

Jackson and the Whigs: 1830–1844

The Mexican War: 1844–1848

1836 Texas declares independence from Mexico Battle of the Alamo Congress refuses to annex Texas
1841 John Tyler becomes president upon Harrison’s death
1842 Webster-Ashburton Treaty ends Aroostook War Congress passes Tariff of 1842
1844 James K. Polk is elected president
1845 United States annexes Texas Congress is presented with Wilmot Proviso
1846 Congress passes Walker Tariff United States and Britain resolve dispute over Oregon Mexican War erupts
1847 General Winfield Scott captures Mexico City
1848 United States and Mexico sign Treaty of Guadalupe Hidalgo
1849 Peak of California Gold Rush
Key People
Daniel Webster -  Secretary of state under Tyler; negotiated Webster-Ashburton Treaty
Frederick Jackson Turner -  Historian of the late 1800s who explored the importance of the frontier in U.S. history

Manifest Destiny

During the 1830s and 1840s, American nationalism and westward expansion had merged into the widespread belief in manifest destiny. Proud of their democratic roots and traditions, faced with a seemingly boundless continent, many Americans thought of themselves as the forbearers of freedom.

Nationalistic revivalist preachers added fuel to the fire by proclaiming that Americans were God’s chosen people and that it was their right and duty to spread democracy and Protestantism from sea to shining sea. Many also looked to nearby Canada and Mexico, and even as far away as South America. Whereas the Old World had been dominated by monarchy and aristocracy, Americans were determined that the whole of the New World would be free.

Western Trails

Settlers moving west took any of several major routes, most of which started in Missouri. Of these, the Oregon Trail is most famous. Hundreds of thousands of Americans moved to Oregon Territory (now Washington, Oregon, and Idaho) during the years before the Civil War, most of them settling in the fertile Willamette Valley.

The Mormon Trail to Utah and Nevada was also popular, as was the Santa Fe Trail to New Mexico, and the California Trail to Sacramento and the San Francisco Bay area. Because there were no railroads in the West, the transcontinental journey had to be made in wagons or on horseback. Thousands even made most of the journey on foot.

Life in the West

People left their homes in the East for new opportunities, for adventure, or for religious reasons—or to strike it rich, after gold was discovered in California in 1848. Life on the trails and on the frontier was difficult because of weather, disease, and bandits, and thousands of travelers never made it to their destinations. Many of the first settlers were criminals who had fled the states to escape sentences or execution. There was little law enforcement except for the occasional band of vigilantes. There were also few or no women in many areas.

Territorial Disputes with Britain

The manifest-destiny fervor exacerbated territorial tensions with Britain—tensions that had been mounting since the War of 1812. Although some disputes had been temporarily settled during Monroe’s and Adams’s presidencies, several major issues remained unresolved.

The Aroostook War

The two sides almost came to blows when frontiersmen in Maine and Canada started a small war for control of land in northern Maine in 1842. This Aroostook War (after the Aroostook River in Maine) convinced both Britain and the United States that a settlement needed to be negotiated before the fighting in the wilderness became a full-scale war. Fortunately, Daniel Webster (who served as Tyler’s secretary of state) and Lord Ashburton of Britain agreed on a permanent border between Maine and Canada in the Webster-Ashburton Treaty of 1842.

Oregon and 54° 40'

Britain and the United States also clashed over the Oregon Territory, and the dispute proved harder to solve. The two countries had occupied the territory jointly until 1828, at which time Britain had offered the United States everything south of the 49th parallel—the present-day border between Washington State and Canada. Most Americans, however, wanted nothing less than the entire territory, everything up to the 54° 40' parallel (up to the southern tip of Alaska). Although Britain had better claims to the land, the number of Americans in the territory far outnumbered the British, who numbered only several hundred. This unresolved issue, a hot topic in the election of 1840, was not resolved until several years later.

The Lone Star Republic

The other major land issue in the 1840s was Texas, which had declared its independence from Mexico in 1836 and had immediately requested U.S. statehood. Northern Whigs and opponents of slavery, however, protested the creation of another state in the South and blocked the move to annex the fledgling country in Congress. The U.S. neutrality pledge also prevented it from interfering. So for the time being, the United States could offer nothing more than formal recognition. Mexico tried several times over the next decade to reconquer their rebellious Texas province without success.

Britain’s Plans for Texas

Forced to protect itself, Texas negotiated trade and security treaties with several European powers. Britain in particular became very interested in Texas: it hoped to use Texas as a buffer to curb U.S. expansion. With the United States unable to expand beyond Texas, Britain hoped to weaken the Monroe Doctrine and perhaps gain new territories in North America again. In addition, Britain hoped that Texas cotton could end England’s dependence on American cotton. American policymakers were furious when they learned of Britain’s plans, so Texas thus became the hottest topic in the election of 1844.

The Significance of the West

Historian Frederick Jackson Turner argued in his 1893 paper “The Significance of the Frontier in American History” that the West and expansionism during the nineteenth century had an extraordinary impact on American government and society. He argued that a seemingly endless frontier made Americans different from Europeans and helped them develop democracy, individualism, and egalitarianism. Though mostly overlooked when it was first published (and still debated among historians today), Turner’s argument has become a landmark work in American historical scholarship.

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