President James Polk, expecting a fast resolution to the Mexican-American War, “requested from Congress in August 1846 a $2 million appropriation for ‘defraying any extraordinary expenses which may be incurred in the intercourse between the United States and foreign nations.'” Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 766 quoting James Polk, Diary, II, 76-77 (Aug. 10, 1846). Shortly after Congress followed this instruction and drafted a bill, David Wilmot of Pennsylvania introduced an amendment to specify that slavery would not be lawful in any territory acquired. See Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 767.
In the Senate, the bill, including Wilmot’s amendment, was endlessly debated and obstructed. See id. Wilmot, a Democrat, felt that President Polk had manipulated his fellow Democrats in pursuing the war. See id. When Congress voted on the appropriation bill, with the Wilmot proviso attached, it was unsuccessful. See id.
Wilmot had “framed his measure as an appeal to the white working class, not as a humanitarian benefit to blacks.” Id. He boasted that the purpose was to “preserve for free white labor a fair country, a rich inheritance, where the sons of toil, of my own race and own color, can live without the disgrace which association with Negro slavery brings upon free labor.” Id. at 768 quoting Charles Going, David Wilmot (New York, 1924), 174.
The Senate did not pass the appropriation bill with the Wilmot proviso. Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 768. However, ten of the northern state legislatures adopted equivalents of the Wilmot proviso. Id. citing Eric Foner, “The Wilmot Proviso Revisited,” JAH 56 (1969), 262-79; Michael Holt, The Fate of Their Country (New York, 2004), 26; Michael Morrison, Slavery and the American West (Chapel Hill, 1997), 40-45, 72-81.
Abolitionists were empowered by this, however, it also identified the opposition to the Mexican-American War. Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 768.
The Wilmot proviso’s impact on the issue of slavery and sectionalism was substantial. Given the fact that northern states were supportive of it, as they were united in their belief that slavery should not be extended, it would change the discussion of fundamental political issues in the late 1840s.
The nature of its emergence, however, makes it particularly notable. In the midst of the Mexican-American War, when the nation’s collective attention was focused on winning the war with Mexico and expanding American territory, the issues of slavery and sectionalism were not quite as contentious as before the war. This made the Wilmot proviso not quite as immediately impactful and contentious as it would have been if introduced in other circumstances.
During times of war and hardship, American discourse can radically change. Even the most fiercely debated issues can be sidelined temporarily. In some cases, this can be beneficial, but in the case of the Wilmot proviso, it only delayed the inevitable discussion of slavery and sectionalism, which would quickly come back to the center of politics after the war.