Expansion and States' Rights
As the United States thrived and flourished during the early nineteenth century, the demand for territorial expansion grew increasingly loud. A growing number of Americans felt the nation's borders were ordained by God to extend from the Atlantic Ocean to the Pacific, a philosophy known as Manifest Destiny. If regions owned by other countries could be purchased, so be it. If not, they were more than likely to be taken by force. The Mexican War (1846–48), for example, was little more than a trumped-up conflict designed by the United States to wrest large tracts of western territory from Mexico when that country refused to sell the desired lands. On February 2, 1848, the Treaty of Guadalupe Hidalgo turned over to the United States 525,000 square miles of territory that would eventually become California, Nevada, Utah, most of Arizona and New Mexico, and parts of Colorado and Wyoming.
Manifest Destiny and the Question of Slavery
The acquisition of this western territory, as well as other tracts that had been acquired earlier, created a growing rift between the North and the South in regard to the issue of slavery and, at the same time, states' rights. The South, naturally, wanted the new territories to allow slavery, but the North did not. The Northwest Ordinance, enacted in 1787, stated that all territories north of the Ohio River were to be free; until 1819, the two regions were equally divided, with eleven states each. However, pending growth required new action.
The first solution was the 1820 Missouri Compromise, legislation that was specifically designed to keep both sides happy. Missouri entered the Union as a slave state and Maine entered as a free state.
By 1850, only a third of Americans lived in the South, compared to half at the beginning of the century. Of the nation's ten largest cities, only New Orleans was located in the South.
The territory acquired as a result of the Mexican War would require another compromise thirty years later. The Compromise of 1850, brokered by Henry Clay with Daniel Webster of Massachusetts, did little to affect the institution of slavery in the United States aside from officially prohibiting it in the District of Columbia. It admitted California into the union as a free state but allowed newly acquired territories to decide for themselves whether slavery should be permitted. Neither side was particularly satisfied with the legislation.
The Debate over States' Rights
The Missouri Compromise and the Compromise of 1850 both dealt in part with an issue of particular sensitivity to the South — states' rights. Many people, especially in the South, felt the federal government had no right to decide important issues within a state, and the shifting balance of power between the federal government and individual states remained a hot-button issue that contributed strongly to the beginning of the Civil War.
The Tenth Amendment states, “the powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the states respectively, or to the people.” To most citizens of the South, this amendment clearly prevented the federal government from interfering in a state's individual affairs — such as the institution of slavery. If changes were to be made, only the population of a given state could make them. In short, the proud Southern states didn't like being told what to do and begged simply to be left alone.
An example of how strongly the Southern states felt about Northern intrusion can be found in South Carolina's 1832 suspension of a heavy 1828 tariff placed on imports at the insistence of Northern merchants. When a South Carolina state convention issued an ordinance nullifying the tariff, it brought the nation to the brink of war. President Andrew Jackson threatened to send federal troops to the port of Charleston to enforce the tariff, and the governor of South Carolina threatened to meet them with an armed militia. War was only averted with the Compromise Tariff of 1833, which gradually reduced tariffs until 1842. As a result, the South Carolina convention voted to repeal the Ordinance of Nullification, ending the crisis.