What Was the Wilmot Proviso?

The Wilmot Proviso Video

Hi, and welcome to this video on the Wilmot Proviso! In this video, we’ll look at the historical context surrounding the proviso and its contents. We’ll then examine what became of the measure and its overall significance.

Polk and the Expansionist Platform

James K. Polk was elected President of the United States in 1844 on an expansionist platform which included the incorporation of Texas into the Union and acquiring Oregon, California, and New Mexico. War with Britain over Oregon was avoided through an 1846 treaty which set the border along the 49th parallel. Mexico was understandably less willing to hand over half of its territory and rebuffed Polk’s offer of $20 million. Polk dispatched a force under the command of Zachary Taylor to the Rio Grande area to provoke a confrontation with the Mexicans. The gambit worked as Taylor’s men came under attack in April and Congress approved a formal declaration of war on May 13th, 1846.

The conflict was highly controversial from the outset and denounced by the Whigs as an aggressive war of conquest. With successes in the opening skirmishes and an overwhelming advantage in military strength, the only real uncertainty over the war was how much would be taken in the peace deal. Just a few months into the conflict, a bill to allocate funds of up to $2 million for peace negotiations was proposed by the president. During the Congressional debate over the bill, David Wilmot of Pennsylvania proposed adding a condition to the release of the funds. Wilmot proclaimed that any territory acquired as a result of negotiations with Mexico would not allow slavery.

The status of slavery in newly-acquired territory was one of the biggest concerns of expansion at the time. Northern opposition to slavery was not always connected to morals; it was also rooted in concern for the significant and disproportionate influence wielded by a slim majority of Southern slave owners. By contrast, the Southern states worried that restricting slavery to the South would see their own interests diminished by a dominant majority of free states. A staunch Democrat and supporter of Martin Van Buren, Wilmot seemed an odd champion in the fight against slavery.

The president was furious when he learned of Wilmot’s rider to his bill, describing it as a “mischievous and foolish amendment”. He later recorded “what connection slavery had with making peace is difficult to conceive.”

Wilmot opposed slavery because it stood in the way of northern white migration. As George Rathburn, a New York Representative and contemporary of Wilmot’s, observed “where slavery exists – slave power prevails.” Wilmot championed the cause not of enslaved African Americans, but of opportunities for northern whites. While opposing the institution of slavery, many northerners were uncomfortable with the polarizing rhetoric of the abolitionists. They believed that if slavery were contained to the South, it would eventually come to an end of its own accord. The Wilmot Proviso offered a political solution and a more palatable alternative to the moral crusade of the abolitionist movement. It would ultimately lead to the Free Soil movement.

The Wilmot Proviso passed the House by 83-64. In the Senate, the proviso faced a stumbling block by the name of Dixon Lewis, who struck down the Wilmot Proviso and the move to vote. Senator John Davis, a Whig who opposed the war and slavery, spoke against the motion. Unaware the House clock was not synchronized with the Senate’s, Davis failed to yield in time for a vote to be held. His inadvertent filibuster killed the Wilmot Proviso for the time being.

In the meantime, Wilmot scraped by in his reelection and met with the president in December 1846. Polk explained to Wilmot that he shared Wilmot’s opposition to the expansion of slavery, but the anti-slavery language of Wilmot’s amendment would endanger any bill being passed. Wilmot agreed not to reintroduce his amendment but would feel honorbound to back any new version of the proviso that might emerge elsewhere.

In January 1847, Preston King added a more forceful rider to the now $3 million appropriation bill. King’s upgrade to the Wilmot Proviso was to assert that slavery would not be permitted in any future territory added to the United States, not just the territory gained from Mexico. Wilmot backed the bill but insisted his support was not based on any abolitionist sympathies but of neutrality. He argued that slavery could not be added to lands where it did not already exist.

The expanded proviso made it through Congress on a vote of 115-106. In the Senate, the pro-slavery counterattack was led by the former Vice-President John C. Calhoun. Calhoun insisted that the move to block slavery in new territories violated the rights of Southerners to migrate to new lands with their own property. He warned that any attempt to contain slavery would ultimately lead to “anarchy, civil war, and widespread disaster.” The $3 million bill was passed with mention of the Wilmot Proviso.

Legacy of the Wilmot Proviso

Polk successfully lobbied enough Democratic Representatives to support his bill without the proviso attached. Polk won the battle but at a huge political cost, as the splits within the Democratic party became a chasm. The Free Soil Party was founded in 1848 and former president Martin Van Buren was chosen as the party’s nominee for the 1848 election.

The crux of the Free Soil movement was that the United States had passed beyond the natural boundaries of slavery and any new territory had to be protected against further encroachment. Wilmot supported Van Buren for president but chose to remain in the Democratic party as a so- called Proviso Democrat and continue the fight against slavery’s expansion.

Though the Wilmot Proviso did not pass, it represented an important milestone in the long political struggle over slavery and laid the foundations for the ultimate demise of the institution.
Okay, before we go, let’s go over a couple of review questions.

Review Questions

1. True or False: The original $2 million bill was issued as a request for funds to facilitate negotiations with Mexico.

The correct answer is True!

Polk requested the money for the potential purpose of securing Mexican land.


2. The Wilmot Proviso stated that…

A. All slavery should be abolished in the U.S.
B. All lands claimed from Mexico must be closed to slavery
C. The U.S. could only claim lands from Mexico that already contained slaves
D. The U.S. must refrain from claiming land from Mexico

The correct answer is B!


That’s all for this review! Thanks for watching, and happy studying!


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by Mometrix Test Preparation | Last Updated: February 9, 2024