Guest Essayist: Professor Joerg Knipprath


The Missouri Compromise of 1820, it has been said often, delayed the Civil War for a generation. The act could not, however, eliminate the reality of slavery and the inherent contradiction of such an institution existing in a society founded on the idea of freedom. The Compromise had loaded the dice in favor of at least a gradual erosion of the slave states’ power, thereby also virtually guaranteeing a serious clash, if those states eventually found themselves in an existential political trap.

The tariff and nullification crises with South Carolina and the political realignment and social upheaval of the Age of Andrew Jackson preoccupied Americans in the period between the Compromise and the Mexican War in 1846. The event of a forthcoming American victory quickly marked that war for many Northerners as a tool for the expansion of the “slave power,” especially coming shortly after the incorporation of Texas into the Union as a slave state. As a strong believer in Manifest Destiny, President Polk welcomed the opportunity to gain California and the Southwest, either by paying off Mexican president Santa Anna or by military conquest. Much of the new territory would lie directly west of the slave states, and anti-war and anti-slavery sentiment in the North overlapped.

As had been the case with the Missouri Compromise, constitutionally and politically, the issue was two-fold. Immediately, there was the question of Congress’s power to ban slavery in the territory and to prevent Southerners from migrating there if they took their slaves. In the longer term loomed the question of whether a state organized in that territory could be admitted as a slave state to maintain the political balance between free and slave states in the Senate. In the midst of the simmering controversy over the war, an obscure Democratic congressman, David Wilmot, dropped a political bomb in the form of an amendment to a bill over war funding. The amendment provided that, inasmuch as the territory now controlled by Mexico was free, “neither slavery nor involuntary servitude shall ever exist” within its boundary.

Though from Pennsylvania, Wilmot was a member of the congressional wing of a radical anti-slavery, pro-Van Buren political faction in New York (the “Barnburners”). Van Buren had been passed over for the nomination in 1844 in favor of James Polk, so that faction was generally opposed to the President. But Wilmot himself had good relationships with the President and many Southerners.

If Wilmot was not a radical, his proposal was. On the surface, it seemed conventional, since Congress several times had legislated about slavery in the territories. Still, to Southerners, the proposal was revolutionary. Since the beginning of the country, as reflected in the statutes that organized the Old Northwest and the Old Southwest, slavery in the territories and in the states had been addressed through geographic division. The Missouri Compromise had made this approach explicit. To the South, this custom had become so established that it had the force of a constitutional settlement. Wilmot’s proposal exploded that accommodation and, hence, to the South, was unconstitutional.

Wilmot’s proposal did not pass. Neither did Polk-backed alternatives in 1846 and 1847 simply to extend the Missouri Compromise to the Pacific. The voting on these proposals was generally sectional, not partisan, a foreboding of the rending of the national fabric in the next decade.

The Wilmot Proviso produced four responses to the question of slavery in the territories and Congress’s power to prohibit it. The radicals in the Democratic Party, along with anti-slavery Whigs and moderate abolitionists, took the Proviso’s position that Congress had full sovereignty over the territories based on its constitutional power to make “all needful Rules and Regulations respecting the Territory or other Property of the United States.” Those groups eventually combined in the Free Soil Party and selected Martin Van Buren as their candidate for president in the 1848 election.

Polk’s unsuccessful proposals represented a second view, namely, that Congress had the power to regulate slavery in the territories, but that the solution was a geographic extension of the dividing line between slave and free territory within the framework of the Missouri Compromise. Had that been adopted, more territory would have been closed to slavery than what was possible through the Compromise of 1850, but abolitionists opposed any slavery in the newly-acquired territory.

The third view was espoused by Senator John C. Calhoun (and by Chief Justice Roger Taney in the Dred Scott case) and was adopted in resolutions of the Virginia legislature in 1847. This “platform of the South” denied congressional power to regulate slavery in the territories because governing sovereignty lay in the states. In respect to territories the federal government acted only as a trustee of the states’ interests. The territories, Calhoun asserted, “belonged to the States United, not to the United States,” in the pithy aphorism by the historian Samuel Eliot Morrison. Congress could neither prohibit slavery nor establish it in the territories by legislation. Of course, the territorial legislatures likewise could not abolish slavery. Only once the territory was ready for statehood could the issue of slave or free be decided. In the meantime, slave-owners must have the same rights of citizenship to take their property into national territory as did emigrants from free states. Slavery would follow the flag. Any interference with those constitutional rights was to be resolved through court cases, not legislation.

The fourth approach to slavery in the territories was “popular sovereignty.” It represented a compromise advocated by moderate Northern Democrats to balance pro-slavery interests and national unity. The slavery issue was not to be decided by Congress in organizing the territory, nor was it to be left open until statehood. Rather, the people of the territories would decide for themselves. Gone would be artificial distinctions based on lines on a map. Rather, those affected most directly would decide through democratic means.

“Popular sovereignty” was grounded philosophically in notions of the social contract and consent of the governed that gave it a thoroughly American pedigree. As Senator Lewis Cass of Michigan, one of the original supporters of this compromise, expressed it, “[L]eave it to the people, who will be affected by this question to adjust it upon their own responsibility, and in their own manner, and we shall render another tribute to the original principles of our government ….”

On a pragmatic level, the doctrine reflected the practice of how territories in fact long had been organized. Local self-government, colorfully described as “squatter sovereignty,” had been the moving force behind the organic growth of institutions within the territories. Congress provided the legal and political framework of government in the enabling laws, but the people built the enduring structures that led to the territories’ eventual recognition as states.

With the ill and exhausted President Polk opting out of re-election, Senator Lewis Cass of Michigan became the Democratic nominee in 1848. Cass, like Polk, was an expansionist. Again like Polk, Cass desired to placate the South for national unity’s sake. His leadership role in formulating “popular sovereignty” as a moderate compromise—with the potential once more to paper over sectional differences on slavery and the territories, as well as solving the more immediate problem of organizing the land newly acquired from Mexico—also made him acceptable to most factions within the party.

The Whigs nominated for President a political novice, Zachary Taylor of Louisiana, “Old Rough-and-Ready,” the hero of the Battle of Buena Vista in the Mexican War. Millard Fillmore was to be Vice President. True, three other generals had been elected president before him (Washington, Jackson, and William Henry Harrison), but they had been involved in politics. Taylor had never even voted in a presidential election. Though a Southerner and slave-holder, he was foremost a unionist and had no strong pro-slavery political sentiments.

The sand in the gears proved to be the third-party candidacy of Martin Van Buren of the Free Soil Party (“Free soil, free speech, free labor, and free men”). He carried no states in the election and drew only 10% of the vote overall, but cost Cass enough votes in New York that the Whigs won the state. With New York’s 36 electoral votes in his column, Taylor won the election with 47.3% of the vote and 163 electoral votes from 15 states. Cass received 42.5% of the vote and 127 electoral votes from 15 states.

Due to Taylor’s Southern background, the election was not sectional. Whigs and Democrats both won Northern and Southern states. However, still waters can run deep, and that seeming unity would soon be severely tested, as the issue of slavery in the territories lurched to its next stage, over the admission of California and the organization of New Mexico Territory. The result, the Compromise of 1850, based partly on Cass’s “popular sovereignty,” would be Senator Henry Clay’s swan song. Then, with the passing of the generation of Senatorial giants Calhoun, Clay, and Webster, the task of holding together a country increasingly rent by the fissure of slavery would fall to Senator Stephen Douglas, the last great advocate of “popular sovereignty,” in the ill-fated Kansas-Nebraska Act of 1854.

An expert on constitutional law, Prof. Joerg W. Knipprath has been interviewed by print and broadcast media on a number of related topics ranging from recent U.S. Supreme Court decisions to presidential succession. He has written opinion pieces and articles on business and securities law as well as constitutional issues, and has focused his more recent research on the effect of judicial review on the evolution of constitutional law. He has also spoken on business law and contemporary constitutional issues before professional and community forums. Read more from Professor Knipprath at:

1 reply
  1. Ralph T. Howarth, Jr.
    Ralph T. Howarth, Jr. says:

    In a republic, it is unjust to subject citizens to laws that they have no means of representing their interests in the making of those laws. This makes somewhat a case for the “popular sovereignty” solution. As a territory, there is not yet a republic; but it is commendable that Congress may make conditions in a territory to operate as close to a republic in concept as the federal constitution has the Article IV republican guarantee clause for statehood.

    Former president Jefferson gave an interesting take on the original Missouri Compromise not only as a proverbial kicking the can down the road, and not only as a compromise that will eventually divide the nation, but he held the opinion that new territories ought to permit both non-slave holders and slave holders alike to migrate. He believed that the amagumum of mixed slave holding and non-slave holding society will eventually win out with abolition as free holders abound.

    See Jefferson’s letter to John Holmes Apr 20, 1820

    There is also little mentioned precedent of Congress actually having the right to ban slavery in a territory. As the Northwest Ordinance banned slavery in the NW Territory under the AoC, and was reissued again as a new ceded federal government from the old confederacy, the First Congress seemed that passed the Bill of Rights the very same month seemed to not be under any disillusion that Congress had no power to ban slavery in a territory.

    Then there are letter exchanges about Missouri statehood that I have read/heard about in the past how the question was raised on what if Missouri became a state but became amenable to the union? The response was that Missouri then would be an independent republic. This was not too strange as Vermont had carved off from New Hampshire and New York. Ran itself as an independent republic for 14 years before entering officially into the union.


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