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[Detail] Experience and personal narrative of Uncle Tom Jones...1858

Slavery and the Territories: The Missouri Compromise and The Wilmot Proviso

In 1817, Missouri applied for admission into the Union as a slave state. This effort threatened the political balance of power in Congress, which consisted of twenty-two states evenly split between the slave and free factions. After years of deliberation, Congressmen Henry Clay and Daniel Webster drafted the Missouri Compromise of 1820. This bill admitted both Maine and Missouri into the Union (as a free and slave state, respectively) and prohibited slavery north of the southern boundary of Missouri, extending across the nation to Mexican territory.

The question of allowing slavery in United States territories was revisited when the Mexican-American War raged from 1846 to 1848 and the Union acquired territories stretching from Texas to the Pacific Northwest. Pennsylvania Congressman David Wilmot called for the prohibition of slavery in these new territories with an attachment to an appropriations bill for establishing the border with Mexico .

Arguments against the Wilmot Proviso came from across the nation. Michigan senator and 1848 presidential candidate, Lewis Cass, called for votes against the attachment in “General Cass on the Wilmot Proviso” with the first of many reasons being: “The present is no proper time for the introduction into the country, and into Congress, of an exciting topic, tending to divide us, when our united exertions are necessary to prosecute the existing war.” An article from the Charleston, South Carolina Mercury echoed Cass’s claim with the assertion that the Wilmot Proviso threatened to subvert the Constitution and is “splitting the Union into sectional parties; it is virtually the first step to a dissolution,” (page 65).

  • Why do you think that Wilmot sought to ban slavery in the western territories?
  • Why did his opposition believe that it was important to defer the question of slavery?
  • Why did the Wilmot Proviso threaten to fuel sectional tensions in Congress?
  • How might such a bill have either caused or created an imbalance of power in Congress?
  • On what basis did General Cass argue that the Wilmot Proviso subverted the Constitution?