The Pre-Civil War Era (1815–1850): Manifest Destiny: 1835–1850

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.