Causation 1800-1848

Expansion of the early American republic

By 1848, the United States had claimed, through diplomacy and warfare, almost the entirety of what is now the continental territory of the country, other than the southern boundaries of modern Arizona and New Mexico - this territory would be acquired in the Gadsden Purchase in the early 1850s. American expansion from “sea to shining sea” provided enormous resources and seemingly boundless landscapes for settlers, both native-born and immigrant, but simultaneously diminished the territorial expanses of indigenous societies and coincided with a dramatic expansion westward of the “peculiar institution” of slavery.

War in the antebellum period

During the first half of the nineteenth century, the United States engaged in a series of large-scale armed conflicts and wars against the Barbary pirates, the United Kingdom, and Mexico as well as with multiple indigenous societies under its legal and military jurisdiction. As you will read about in the next chapter, many Americans subscribed to a philosophy known as manifest destiny, the idea that Americans were fated and tasked with extending their culture, economy, and laws over the entire continental landscape. Native American, Mexican, Canadian, and European observers witnessed these developments with alacrity as they often viewed American expansion as detrimental to their respective security and territorial domains and ambitions.

America on the world stage

As the United States expanded geographically, its government began engaging in more sustained diplomatic activity. American representatives, then called ministers and not ambassadors, sought to advance the country’s economic and political priorities in foreign capitals while presidential emissaries met with representatives from Native American societies. Diplomatic negotiations were essential in defusing conflicts, including with the Barbary pirates, and sometimes preventing war with the United Kingdom, France, Spain and indigenous societies, while still advancing American political, economic and security priorities such as more clearly establishing the country’s geographic boundaries and warning European countries against renewed colonialism in the western hemisphere.

Technological progress and demographic shifts

As Americans increasingly moved westward and began organizing territories west of the Mississippi River, demands for greater communications and transportation networks arose. Americans increasingly embraced steamships, railroads and telegraphs as vital mechanisms for expanded commercial and cultural exchanges. New towns and cities developed, including Chicago, as vital railroad hubs while in the southern states and territories, thousands of settlers benefited from the unpaid labor of enslaved persons as well as the forced expulsion of indigenous peoples.

Democracy for more, but not for all

During the first half of the 19th century, considerable progress was made in terms of expanding voting rights to almost all white men as states rescinded previous property requirements, but this expansion of adult white male suffrage was not matched by any expansion of voting rights for women or free African Americans. Petitions calling for the expansion of suffrage to women and African Americans as well as the Seneca Falls Convention in July 1848 and later the valiant and valuable military contributions of African American men increased pressure on state and federal authorities to expand voting rights.

Sectional tensions

Throughout the antebellum period, increasing differences between northern, southern and western states and territories, most frequently involving disputes about the expansion of slavery but also involving cultural, economic and political disagreements, led to greater sectional tensions. In the War of 1812, many people in New England disapproved of the war and what they perceived as its negative consequences for their region as well as the entrenched dominance of the Virginia dynasty. During the Nullification crisis of the early 1830s, South Carolinians and many other southerners objected to what they considered to be excessive tariffs intended to benefit northern manufacturers. With the Mexican-American War, which will be discussed further in the next chapter, disagreements over the expansion of slavery into new territories further divided the country; within 13 years of the end of the war, the United States would confront its own civil war.

During the first half of the 19th century, the United States expanded westward from the Mississippi River to the Pacific Ocean; the country also incorporated Florida, Texas, the desert southwest of Arizona and New Mexico, and the Pacific northwest of Oregon and Washington.

The United States emerged as an important new power in hemispheric and global diplomacy, including with the issuance of the Monroe Doctrine. American diplomatic efforts both increased the territorial expanse of the country and infuriated Canada, and its British colonial authorities, and Mexico.

Sectional disputes over the expansion of slavery into newly acquired territories increased tensions throughout the country; these disputes were grounded in questions of morality, law, economics, and culture.

The United States increased the number of adult white men who could vote during the first half of the 19th century but prohibited women and free African Americans from voting.