Introduction

When thirteen American colonies, clustered on the Atlantic Coast of North America, declared independence from the British Empire in 1776, Indian people and European imperial powers controlled the vast expanses of the North American con­tinent.

Yet the same men who decried empire in 1776, and emerged as the leaders of the newly independent United States in 1783, almost immediately embarked upon a program of territorial expansion, acquiring and settling new territory through the agency of their new government. It was no coincidence that these republican citizens called themselves Americans, a name that theoretically embraced two continents. They had vast ambitions, and from the beginning were relentlessly mo­bile, moving with a frequency that astounded European observers. Just 80 years after independence, the United States embraced a continental empire, and at the close of the nineteenth century, formally governed colonies in the Caribbean and Pacific Ocean.²

What is perhaps most remarkable about America's dramatic territorial growth is that it occurred in a nation that continued to vehemently disavow imperi­alism. For the vast majority of the nineteenth century, national political leaders, and the white men who elected them, loudly, and for the most part sincerely,

¹ Portions of this chapter are based on Greenberg 2005, 2012. Full documentation can be found in those works.

² Seymour 2012, 1-3; Wood 2009, 357-399.

Amy S. Greenberg, US Expansionism during the Nineteenth Century In: The Oxford World History of Empire. Edited by: Peter Fibiger Bang, C.A. Bayly, Walter Scheidel, Oxford University Press (2021). © Oxford University Press.

DOI: 10.1093/oso/9780197532768.003.0037.

1012 AMY S. GREENBERG

Map 37.1 Expansion of the United States.

Source: http://www.legendsofamerica.com/photos-americanhistory/westernexpansionmap.jpg. Copyright: Bormay & Co., 1906, Map of the United States Showing Acquisition of Territory.

condemned current and previous empires, along with the colonialism and other political evils they believed inherent in imperialism. The pursuit of empire was necessarily believed to lead to political corruption and internal collapse. The United States set out to be a nation unlike any other: a republic governed by an educated citizenry for the good of all, and a significant minority believed extended territory incompatible with republican government. Yet there was nothing accidental about the growth of the United States. Territorial expan­sion involved concerted effort on the part of politicians and settlers, treaties with European nation-states and native peoples, and the forced dislocation of Indian people from their land.

Americans were able to simultaneously disavow and build an empire thanks to a mid- nineteenth- century ideology known as Manifest Destiny. In the 1840s Manifest Destiny accelerated western settlement and provided a rationale for continued con­tinental expansion. It cast western expansion as natural and predetermined, and justified a policy of brutal racially based warfare against both Indian people and Mexicans. Starting in the late 1830s, American politicians asserted, and many citizens believed, that God had divinely ordained the United States to grow and spread across the continent.

The fracturing of the national consensus over the future of America's Manifest Destiny in the 1850s was directly related to the rise of the sectionalism that terri­torial expansion helped unleash. When Northerners and Southerners refused to compromise over the status of slavery in newly won territories, the only thing still manifest was the inevitability of a Civil War. After the war, Manifest Destiny went into eclipse. For 30 years after the Civil War, Americans remembered Manifest Destiny as an antebellum relic, and American nationalists pushed to control international trade rather than foreign land. But the ideology experienced a re­birth in 1898 when supporters of war with Spain claimed that America's Manifest Destiny had worldwide dimensions. This chapter will provide an overview of how Manifest Destiny helped create a North American empire that was at once very familiar, and in other ways strikingly different from those that had come before.