The Wilmot Proviso: Definition, Date, and Purpose

| | October 10, 2023

Throughout the 19th century, during the period known as the Antebellum Era, Congress, and American society as a whole, was tense. 

Northerners and Southerners, who never really got along anyway, were engaging in a White-hot (see what we did there?) debate over the issue of slavery — specifically, whether or not it should be permitted in the new territories the US had purchased, first from France in the Louisiana Purchase and later acquired from Mexico as a result of the Mexican-American War.

Eventually, the anti-slavery movement gained enough support throughout the more-populous North, and by 1860, slavery seemed doomed. So, in response, 13 Southern states announced they would secede from the Union and form their own nation, where slavery would be tolerated and promoted. 

So there.

But while the sectional differences that existed in the U.S since the birth of the nation likely made war inevitable, there were a few moments on the Antebellum timeline that made everyone in the new nation keenly aware that the different visions for the country would likely need to be resolved on the battlefield. 

The Wilmot Proviso was one of these moments, and although it was nothing more than a proposed amendment to a bill that failed to make it into the final version of the law, it played a pivotal role in adding fuel to the sectional fire and bringing about the American Civil War.   

What Was the Wilmot Proviso?

The Wilmot Proviso was an unsuccessful proposal in August 8 1846 by the Democrats in the U.S Congress to ban slavery in the territory recently acquired from Mexico in the Mexican-American War.

It was proposed by Senator David Wilmot during a late-night special session of Congress that had met to review the Appropriations Bill initiated by president James K. Polk requesting $2 million to settle negotiations with Mexico at the close of the war (which, at the time, was just two months old). 

Just a short paragraph of the document, the Wilmot Proviso shook the American political system at the time; the original text read: 

Provided, That, as an express and fundamental condition to the acquisition of any territory from the Republic of Mexico by the United States, by virtue of any treaty which may be negotiated between them, and to the use by the Executive of the moneys herein appropriated, neither slavery nor involuntary servitude shall ever exist in any part of said territory, except for crime, whereof the party shall first be duly convicted.

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In the end, Polk’s bill passed the House with the Wilmot Proviso included, but it was struck down by the Senate which passed the original bill without amendment and sent it back to the House. There, it was passed after several representatives who had originally voted for the bill with the amendment changed their minds, not seeing the slavery issue as one worthy of ruining an otherwise routine bill.

This meant Polk got his money, but also that the Senate did nothing to address the question of bondage.

Later Versions of the Wilmot Proviso

This scene played out again in 1847, when Northern Democrats and other abolitionists tried to attach a similar clause to the $3 Million Dollar Appropriations Bill — a new bill proposed by Polk that now asked for $3 million dollars to negotiate with Mexico — and again in 1848, when Congress was debating and ultimately ratifying the Treaty of Guadalupe-Hidalgo to end the war with Mexico.

While the amendment was never included in any bill, it awoke a sleeping beast in American politics: the debate over slavery . This ever-present stain on America’s slave-grown cotton shirt was once again made the focal point of public discussion. But soon, there would be no more short-term answers.

READ MORE: Who Invented the Cotton Gin? Eli Whitney and Cotton Gin Impact on America

For several years, the Wilmot Proviso was offered as an amendment to many bills, it passed the house but it was never approved by the Senate. However, the repeated introduction of the Wilmot Proviso kept the debate of slavery before the Congress and the nation.

Why Did The Wilmot Proviso Happen?

David Wilmot proposed the Wilmot Proviso under the direction of a group of Northern Democrats and abolitionists who were hoping to provoke more debate and action around the issue of slavery, looking to advance the process of eliminating it from the United States. 

It’s likely they knew the amendment wouldn’t pass, but by proposing it and bringing it to a vote, they forced the country to pick sides, widening the already-vast gap between the various visions Americans had for the nation’s future. 

Manifest Destiny and the Expansion of Slavery

As the U.S grew up over the course of the 19th century, the Western frontier became a symbol for American identity. Those who were unhappy with their lot in life could move west to start anew; settling the land and creating a potentially prosperous life for themselves. 

This shared, unifying opportunity for White people defined an era, and the prosperity it brought led to the widespread belief that it was America’s destiny to spread its wings and “civilize” the continent. 

We now call this cultural phenomenon “Manifest Destiny.” The term wasn’t coined until 1839, though it had been happening without the name for decades.

However, while most Americans agreed the United States was destined to expand westward and spread its influence, the understanding of what this influence would look like varied depending on where people lived, mainly because of the issue of slavery.

In short, the North, which had abolished slavery by 1803, had come to see the institution as not only a hindrance to America’s prosperity but also as a mechanism for inflating the power of a small section of Southern society — the wealthy slaveholder class that originated from the Deep South (Louisiana, South Carolina, Georgia, Alabama, and, to a lesser extent, Florida). 

As a result, most Northerners wanted to keep slavery out of these new territories, as allowing it would deny them the golden opportunities the frontier had to offer. The South’s powerful elite, on the other hand, wanted to see slavery flourish in these new territories. The more land and slaves they could own, the more power they had. 

So, each time the U.S acquired more territory during the 19th century, the debate over slavery was thrust to the forefront of American politics. 

The first instance occurred in 1820 when Missouri applied to join the Union as a slave state. A fierce debate erupted but was eventually settled with the Missouri Compromise. 

This quieted things down for a while, but over the next 28 years the United States continued to grow, and as the North and South developed in distinct, different ways, the issue of slavery loomed ominously in the background, waiting for the right moment to jump in and split the nation down the middle so deeply that only war could bring the two sides back together. 

The Mexican War

The context that forced the slavery question back into the fray of American politics formed in 1846, when the United States was at war with Mexico over a border dispute with Texas (but everyone knows it was actually just a chance to beat up on the newly-independent and weak Mexico, and also take its territory — an opinion held by the Whig party at the time, including a young representative from Illinois named Abraham Lincoln). 

Shortly after the breakout of fighting, the U.S quickly captured the territories of New Mexico and California, which Mexico had failed to settle with citizens and secure with soldiers.

This, along with the political turmoil going on in the very young independent state, basically ended Mexico’s likelihood of winning the Mexican war that they had little chance of winning to begin with.  

The US acquired from Mexico a significant amount of territory throughout the Mexican war, preventing Mexico from ever taking it back. Yet fighting continued for another two years, ending with the signing of the Treaty of Guadalupe-Hidalgo in 1848. 

And as a Manifest Destiny-obsessed American population watched this, the country began to lick its chops. California, New Mexico, Utah, Colorado — the frontier. New lives. New prosperity. New America. Unsettled land, where Americans could find a fresh start and the type of freedom only owning your own land can provide. 

It was the fertile soil the new nation needed to plant its seeds and grow into the prosperous land it would become. But, perhaps more importantly, it was the chance for the nation to collectively dream of a bright future, one that it could work towards and realize with its own hands, backs, and minds. 

The Wilmot Proviso

Because all this new land was, well, new, there were no laws written to govern it. Specifically, no one knew if slavery was to be allowed. 

The two sides took their usual positions — the North was anti-slavery in the new territories and the South all for it — but they only had to do so because of the Wilmot Proviso. 

Eventually, the Compromise of 1850 brought the debate to an end, but neither side was satisfied with the result, and both were becoming increasingly cynical about resolving this issue diplomatically.

What Was The Effect of the Wilmot Proviso?

The Wilmot Proviso drove a wedge directly through the heart of American politics. Those who had previously spoken out about limiting the institution of slavery had to prove they were for real, and those who had not spoken up, but who had large contingents of voters who opposed the extension of slavery, needed to choose a side. 

Once this happened, the line between the North and the South became more pronounced than ever before. Northern Democrats overwhelmingly supported the Wilmot Proviso, so much so that it passed in the House (which, in 1846, was controlled by a Democratic majority, but that was influenced more heavily by the more populous North), but Southern Democrats obviously did not, which is why it failed in the Senate (which provided each state with an equal number of votes, a condition that made the differences in population between the two less important, giving the Southern slaveholders more influence). 

As a result, the bill with the Wilmot Proviso attached was dead on arrival. 

This meant there were members of the same party voting differently on an issue almost exclusively because of where they were from. For Northern Democrats, this meant betraying their Southern party brethren.

But at the same time, in this moment of history, few Senators chose to do this as they felt passing the funding bill was more important than solving the slavery question — an issue that had always ground American lawmaking to a halt.

The dramatic differences between Northern and Southern society were making it increasingly difficult for Northern politicians to side with their fellow Southerners on almost any issue.

As a result of the process that the Wilmot Proviso only accelerated, factions from the North slowly started to break away from the two main parties at the time — the Whigs and the Democrats — to form their own parties. And these parties had an immediate influence in American politics, starting with the Free Soil Party, the Know-Nothings, and the Liberty Party.

The stubborn revivals of the Wilmot Proviso served a purpose as it kept the issue of enslavement alive in Congress and thus before the American people.

The issue, however, did not die completely. One response to the Wilmot Proviso was the concept of “popular sovereignty,” which was first proposed by a Michigan senator, Lewis Cass, in 1848. The idea that settlers in the state would decide the issue became a constant theme for Senator Stephen Douglas in the 1850s.

The Rise of the Republican Party and The Outbreak of War

The formation of new political parties intensified until 1854, when the slavery question was once again brought to dominate the debates in Washington. 

Stephen A. Douglas’ Kansas-Nebraska Act hoped to undo the Missouri Compromise and allow people living in organized territories to vote on the issue of slavery themselves, a move he hoped would end the slavery debate once and for all. 

But it had almost the exact opposite effect.

The Kansas-Nebraska Act passed and became law, but it sent the nation closer to war. It sparked violence in Kansas between settlers, a time known as Bleeding Kansas, and it caused a wave of Northern Whigs and Democrats to leave their respective parties and join forces with the various anti-slavery factions to form the Republican Party.

The Republican Party was unique in that it depended on an entirely Northern base, and as it quickly grew in prominence, the North was able to seize control of all three branches of government by 1860, taking the House and the Senate and electing Abraham Lincoln as president. 

Lincoln’s election proved that the South’s biggest fear had been realized. They’d been shut out of the federal government, and slavery, as a result, was doomed. 

So petrified, were they, of a freer society where people couldn’t be owned as property, the slave-loving South had no other choice but to withdraw from the Union, even if it meant provoking a civil war.

This is the chain of events set off in part by David Wilmot, when he proposed the Wilmot Proviso to a funding bill for the Mexican-American War.

It wasn’t all his fault, of course, but he did much more than most to aid in the sectional division of the United States that ultimately caused the bloodiest war in American history.

Who Was David Wilmot?

Considering how much of a ruckus Senator David Wilmot caused in 1846, it’s normal to wonder: who was this guy? He must have been some eager, hotshot rookie Senator who was trying to make a name for himself by starting something, right?

It turns out David Wilmot wasn’t really much of anybody until The Wilmot Proviso. In fact, the Wilmot Proviso wasn’t even really his idea. He was part of a group of Northern Democrats interested in pushing the issue of slavery in the territories front and center in the House of Representatives, and they nominated him to be the one to raise the amendment and sponsor its passage.

He had good relations with many Southern senators, and would therefore easily be granted the floor during the debate over the bill.

Lucky him.

Not surprisingly, though, after the Wilmot Proviso, Wilmot’s influence in American politics grew. He went on to become a member of the Free Soilers.

Free Soil Party was minor but influential political party in the pre-Civil War period of American history that opposed the extension of slavery into the western territories.

In 1848 the Free Soil Party nominated Martin Van Buren to head its ticket. Though the party polled only 10 percent of the popular vote in the presidential election that year, it weakened the regular Democratic candidate in New York and contributed to the election of the Whig candidate Gen. Zachary Taylor as president.

Martin Van Buren would go on to serve as the eighth president of the United States from 1837 to 1841. A founder of the Democratic Party, he had previously served as the ninth governor of New York, the tenth United States secretary of state, and the eighth vice president of the United States.

Van Buren, however, lost his 1840 reelection bid to the Whig nominee, William Henry Harrison, thanks in part to the poor economic conditions surrounding the Panic of 1837.

The Free-Soil vote was reduced to 5 percent in 1852, when John P. Hale was the presidential nominee. Nevertheless, a dozen Free Soil congressmen later held the balance of power in the House of Representatives, thus wielding considerable influence. In addition, the party was well represented in several state legislatures. In 1854 the disorganized remnants of the party were absorbed into the newly formed Republican Party, which carried the Free Soil idea of opposing the extension of slavery one step further by condemning slavery as a moral evil as well.

And, after the Free Soilers merged with the many other new parties at the time to become the Republican party, Wilmot became a prominent Republican throughout the 1850s and 1860s.

But he’ll always be remembered as the guy who introduced a minor, yet monumental, amendment to a bill proposed in 1846 that dramatically altered the course of US history and set it on a direct path to war.

The creation of the Republican Party in 1854 was based on an antislavery platform that endorsed the Wilmot Proviso. The prohibition of slavery in any new territories became a party tenet, with Wilmot himself emerging as Republican Party leader. The Wilmot Proviso, while unsuccessful as a congressional amendment, proved to be a battle cry for opponents of slavery.

READ MORE: The Three-Fifths Compromise

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