What was Manifest Destiny?

Manifest Destiny was the nineteenth century belief that the United States was divinely ordained to expand its territory and institutions across the North American continent from the Atlantic to the Pacific. The phrase was coined by journalist John Louis O'Sullivan in the July to August 1845 issue of the United States Magazine and Democratic Review, in an article advocating annexation of Texas. He wrote that other nations had no right to oppose what was the fulfillment of our manifest destiny to overspread the continent allotted by Providence for the free development of our yearly multiplying millions. The phrase caught on instantly and became shorthand for an entire cluster of beliefs about American expansion.

The doctrine had three intertwined components. The first was racial and religious. Many Anglo-American Protestants believed God had granted the continent to a particular people for a particular purpose, often described as spreading civilization, Christianity, and republican government. This belief mixed with prevailing racial hierarchies that placed Anglo-Saxons above Native peoples and Mexicans, justifying displacement and conquest as part of progress.

The second component was political and economic. Westward expansion would provide land for American farmers, secure markets for Atlantic merchants, and prevent rival European powers from establishing themselves on the Pacific coast. Population growth from a relatively rapid birth rate and waves of European immigration created pressure for new agricultural land.

The third component was strategic. Continental dominance would secure the United States against foreign threats and give it command of Pacific trade with Asia.

Manifest Destiny justified, among other things, the annexation of Texas in 1845, the Oregon Treaty of June 15, 1846 settling the Pacific Northwest boundary at the 49th parallel with Britain, the Mexican-American War from 1846 to 1848 that produced the Mexican Cession of 525,000 square miles, the Gadsden Purchase of 1854 adding 30,000 square miles for a southern railroad route, and constant pressure on Native nations to cede land.

The doctrine was not universally accepted. Whigs including Henry Clay and Daniel Webster opposed expansion as likely to inflame sectional conflict over slavery and to require expensive wars. Abolitionists such as Frederick Douglass and William Lloyd Garrison condemned expansion as an extension of the Slave Power. Henry David Thoreau refused to pay taxes to support the Mexican-American War in 1846, an act of civil disobedience that influenced Mahatma Gandhi and Martin Luther King Jr.

By the late nineteenth century the term shaded into overseas imperialism, justifying the Spanish-American War of 1898 and the acquisition of Hawaii, Puerto Rico, Guam, and the Philippines. Modern historians treat Manifest Destiny as both a cultural ideology and a rationalization for displacement and conquest.