Missouri Compromise Summary

  • Last updated on November 10, 2022

By allowing Missouri to enter the union as a slave state, while Maine entered as a free state, this congressional measure helped preserve the delicate balance between northern and southern sectional interests for more than three decades.

Summary of Event

Between 1818 and 1819, representatives from both Missouri and Maine petitioned the U.S. Congress to admit their territories to the union as states. The Missouri Territory had been created from the Louisiana Purchase (1803) and was promised constitutional protection. However, Congress could not decide if the right of property applied to the institution of slavery. The question at issues was whether slavery should be allowed in Missouri and the rest of the Louisiana Purchase, or did Congress have the moral responsibility to rectify the issue of slavery that had been avoided since the Constitutional Convention of 1787. It would take three sessions of Congress between 1818 and 1821 before Missouri was fully admitted as a state. The issue of slavery sparked by the ensuing debate spread throughout the country and threatened to cause disunion between the northern and southern regions of the United States. Missouri Compromise (1820) Congress, U.S.;Missouri Compromise (1820) Slavery;and Missouri Compromise[Missouri Compromise] Maine;and Missouri Compromise[Missouri Compromise] Congress, U.S.;Missouri Compromise (1820) [kw]Missouri Compromise (Mar. 3, 1820) [kw]Compromise, Missouri (Mar. 3, 1820) Missouri Compromise (1820) Congress, U.S.;Missouri Compromise (1820) Slavery;and Missouri Compromise[Missouri Compromise] Maine;and Missouri Compromise[Missouri Compromise] Congress, U.S.;Missouri Compromise (1820) [g]United States;Mar. 3, 1820: Missouri Compromise[1110] [c]Laws, acts, and legal history;Mar. 3, 1820: Missouri Compromise[1110] [c]Civil rights and liberties;Mar. 3, 1820: Missouri Compromise[1110] Clay, Henry [p]Clay, Henry;and Missouri Compromise[Missouri Compromise] Tallmadge, James Thomas, Jesse Burgess Monroe, James [p]Monroe, James;and Missouri Compromise[Missouri Compromise]

At the time Missouri and Maine applied for statehood, the union had exactly eleven free states and eleven slave states. This political balance had been achieved since 1789 by alternately admitting slave and free states, whose status was determined by each state’s geographical location and its region’s past history with regard to slavery. This arrangement ensued that each section of the country had an equal number of senators, and it attempted to equalize representation in the House of Representatives through the three-fifths clause.

The three-fifths clause, added to the final draft of the Constitution Constitution, U.S.;three-fifths clause[Three fifths clause] in 1789, allowed slave states to count each slave as three-fifths of a person to balance their representative power against that of the more densely populated North. Nevertheless, the North had a majority of representatives in Congress (105 to 81). Missouri’s admission as a free or slave state therefore became an important issue in the very body that would resolve it. Missouri threatened either to extend the influence of the industrial free North in the Senate or to provide the majority to the agrarian slaveholding South.

In 1818, the boundaries of Missouri Territory were approximately the same as those of the modern state, and the territory was estimated to contain two thousand to three thousand slaves. Slavery in Missouri Missouri;slavery was a historical by-product of prior French and Spanish colonial policies. Representatives from Missouri reasoned that slavery should be allowed to continue there as it had in other territories that had been granted statehood since 1789.

In February, 1819, the House of Representatives responded to this debate by adopting an amendment that Representative James Tallmadge Tallmadge, James of New York proposed to attach to the bill allowing Missouri to frame a state constitution. The two clauses in the Tallmadge amendment would restrict the expansion of slavery in Missouri and provide that all children born to slaves would become free at the age of twenty-five. Both clauses of his amendment passed the House. Southern senators were shocked by the bitterness of the debate Debates;Missouri Compromise in the House and the ability of the North to muster votes. They saw the Tallmadge amendment as the first step in eliminating the expansion of slavery in the nation as a whole. Voting along sectional lines, the Senate rejected both clauses.

Congress then adjourned until December 6, 1819. During the interim period, Maine framed a constitution and applied for admission to the union as a free state. Maine had originally been incorporated into the Massachusetts Bay Colony in 1691 but had started to agitate for separate statehood during the War of 1812. Its application for statehood as a free state seemed to provide a possible solution to the Missouri debate that threatened the stability of the young nation.

On February 18, 1820, the Senate Judiciary Committee joined the Missouri and Maine measures and the Senate passed both Maine’s and Missouri’s applications for statehood but without mentioning slavery. This infuriated Maine, which had, as part of Massachusetts, Massachusetts;and Maine[Maine] Maine;and Massachusetts[Massachusetts] outlawed slavery in 1780. What should have been a routine confirmation of new states became part of the most explosive issue to face the country. Maine was to be allowed to separate from Massachusetts and gain statehood, so long as Congress approved its application by March 4, 1820, or its nine counties would revert to Massachusetts. Even so, many of Maine’s constituency urged that Maine’s application fail so that slavery would not spread into Missouri.

Senator Jesse Burgess Thomas Thomas, Jesse Burgess of Illinois offered a compromise amendment to the Senate bill that would admit Missouri as a slave state with the proviso that the remaining territories in the Louisiana Purchase above 36° 30′ north latitude, Missouri’s southern border, would be free of slavery. The northern-controlled House responded by rejecting Thomas’s amendment and instead passed a proviso prohibiting the further introduction of slavery anywhere in the United States. The result was polarization along sectional lines. In turn, the Senate struck out the antislavery provision and added the Thomas amendment. Thus began the final debate over whether slavery would be allowed to expand.

Senator Rufus King King, Rufus of New York continued the debate by stating that Congress, under Article IV, section 3 of the Constitution, was empowered to exclude slavery from the territory and to make slavery an issue for statehood. “New states may be admitted by the Congress into this Union.” A precedent had been established under in the Northwest Ordinance of 1787 Northwest Ordinance (1787);and slavery[Slavery] , which forbade slavery in lands above the Ohio River. Therefore, in the minds of many of the northern congressmen, they should take this opportunity to eliminate slavery from any point west of the Mississippi. In response, Senator William Pickering Pickering, William of Maryland argued that because the United States was made up of equal numbers of slave and free states, Missouri should be allowed to determine its own fate.

Missouri responded with anger and frustration, asserting that the issue was not about slavery but rather the issue of state sovereignty. Congress had delayed Missouri’s admission for several years. Missouri, like other states, had the right to choose its own property laws. In Missouri, as well as the rest of the South, the issue swung from one dealing with slavery to one dealing with property rights and the equality of states within the United States. These issues captured the attention of citizens throughout the country and led to heated debates on all levels. For the first time, slavery was being justified and defended as a good way of life not only by southern politicians but also by the southern clergy. Would the country be influenced by restrictionists who sought to control this institution, or would states’ rights be preserved?

A compromise was eventually reached, between the two houses, in a conference formed to break the deadlock. Speaker of the House Henry Clay Clay, Henry [p]Clay, Henry;and Missouri Compromise[Missouri Compromise] of Kentucky stated that he would not support Maine’s admission unless Missouri was admitted without restrictions. The Senate took the House bill and inserted the Thomas amendment. On March 3, 1820, the House under Clay’s leadership voted to admit Maine as a free state and Missouri as a slave state and restricted slavery north of 36° 30′. It is interesting to note that seven of Maine’s nine representatives in the Massachusetts state delegation voted against Maine’s admission so that their state would not be used to provide a solution to the slavery issue.

Missouri continued to be an issue when it presented a state constitution Missouri;constitution State constitutions;Missouri in November, 1820. As if to get the final word, the Missouri constitutional convention had incorporated into its constitution a provision excluding free blacks and mulattoes Mulattoes from the state. This provision incited the antislavery factions in the Senate and House and threatened to destroy the fragile compromise. A “Second Missouri Compromise” was needed that would state that Missouri would not gain admission as a state unless its legislature assured Congress that it would not seek to abridge the rights of citizens. The Missouri legislature agreed to this in June, 1821. On August 10, 1821, President James Monroe Monroe, James [p]Monroe, James;and Missouri Compromise[Missouri Compromise] admitted Missouri as the twenty-fourth state. After waiting a short time, Missouri’s state legislature sought to have the last say when it approved statutes forbidding free blacks from entering the state.


The Missouri Compromise would stand until Congress’s passage of the Kansas-Nebraska Act in 1854. Until that time, the Missouri Compromise served to mark a clear delineation between the growing regional and sectional problems of the North and South and made states’ rights the rallying cry for the South until the Civil War (1861-1865) Civil War, U.S. (1861-1865);and Missouri Compromise[Missouri Compromise] . In 1857, Missouri would again become the focus of a national debate on slavery when the Dred Scott case reached the U.S. Supreme Court, whose ruling nullified the principles of the Missouri Compromise.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Brown, Richard H. The Missouri Compromise: Political Statesmanship or Unwise Evasion? Boston: D. C. Heath, 1964. Contains primary source material showing views of contemporary leaders and varying perspectives of historians.
  • citation-type="booksimple"

    xlink:type="simple">Clark, Charles E. Maine: A Bicentennial History. New York: W. W. Norton, 1977. Condensed overview of Maine history.
  • citation-type="booksimple"

    xlink:type="simple">Cunningham, Noble E., Jr. The Presidency of James Monroe. Lawrence: University Press of Kansas, 1996. Study of the major domestic and foreign policy issues that Monroe faced during his two terms in office, including the Missouri Compromise.
  • citation-type="booksimple"

    xlink:type="simple">Hurt, R. Douglas. Agriculture and Slavery in Missouri’s Little Dixie. Columbia: University of Missouri Press, 1992. A study of the political and legal impact of the Missouri Compromise during the antebellum era in a seven-county area along the Missouri River.
  • citation-type="booksimple"

    xlink:type="simple">McPherson, James M. The Battle Cry of Freedom: The Civil War Era. Oxford, England: Oxford University Press, 1988. Definitive perspective on the sectional differences leading up to and through the Civil War era.
  • citation-type="booksimple"

    xlink:type="simple">Moore, Glover. The Missouri Controversy, 1819-1821. Gloucester, Mass.: Peter Smith, 1967. A significant monograph on the political compromise that signaled nineteenth century sectional controversies during the antebellum era.
  • citation-type="booksimple"

    xlink:type="simple">Nagel, Paul C. Missouri: A Bicentennial History. New York: W. W. Norton, 1977. Condensed overview of Missouri history by a leading historian.
  • citation-type="booksimple"

    xlink:type="simple">Nash, Gary B., ed. The American People: Creating a Nation and a Society. 2d ed. New York: Harper & Row, 1990. Overview of American history that places the Missouri Compromise in a national historical context.
  • citation-type="booksimple"

    xlink:type="simple">Shankman, Kimberly Christner. Compromise and the Constitution: The Political Thought of Henry Clay. Lanham, Md.: Lexington Books, 1999. Examination of the political thinking of the man who was Speaker of the House of Representatives at the time of the Missouri Compromise.

Louisiana Purchase

Congress Bans Importation of African Slaves

U.S. Election of 1824

Webster and Hayne Debate Slavery and Westward Expansion

Compromise of 1850

Congress Passes the Kansas-Nebraska Act

Bleeding Kansas

Dred Scott v. Sandford

Lincoln-Douglas Debates

Related Articles in <i>Great Lives from History: The Nineteenth Century, 1801-1900</i>

Henry Clay; James Monroe; Roger Brooke Taney. Missouri Compromise (1820) Congress, U.S.;Missouri Compromise (1820) Slavery;and Missouri Compromise[Missouri Compromise] Maine;and Missouri Compromise[Missouri Compromise] Congress, U.S.;Missouri Compromise (1820)

Categories: History