Missouri Compromise, 1820-21, measures passed by the U.S. Congress to end the first of a series of crises concerning the extension of slavery.

By 1818, Missouri Territory had gained sufficient population to warrant its admission into the Union as a state. Its settlers came largely from the South, and it was expected that Missouri would be a slave state. To a statehood bill brought before the House of Representatives, James Tallmadge of New York proposed an amendment that would forbid importation of slaves and would bring about the ultimate emancipation of all slaves born in Missouri. This amendment passed the House (Feb., 1819), but not the Senate. The bitterness of the debates sharply emphasized the sectional division of the United States.

In Jan., 1820, a bill to admit Maine as a state passed the House. The admission of Alabama as a slave state in 1819 had brought the slave states and free states to equal representation in the Senate, and it was seen that by pairing Maine (certain to be a free state) and Missouri, this equality would be maintained. The two bills were joined as one in the Senate, with the clause forbidding slavery in Missouri replaced by a measure prohibiting slavery in the remainder of the Louisiana Purchase north of 36°30'N lat. (the southern boundary of Missouri). The House rejected this compromise bill, but after a conference committee of members of both houses was appointed, the bills were treated separately, and in Mar., 1820, Maine was made a state and Missouri was authorized to adopt a constitution having no restrictions on slavery.

A provision in the Missouri constitution barring the immigration of free blacks to the state was objectionable to many Northern Congressmen, and necessitated another congressional compromise. Not until the Missouri legislature pledged that nothing in its constitution would be interpreted to abridge the rights of citizens of the United States was the charter approved and Missouri admitted to the Union (Aug., 1821). Henry Clay, as speaker of the House, did much to secure passage of the compromise—so much, in fact, that he is generally regarded as its author, even though Senator Jesse B. Thomas of Illinois was far more responsible for the first bill. The 36°30' proviso held until 1854, when the Kansas-Nebraska Act repealed the Missouri Compromise.

Crittenden Compromise, in U.S. history, unsuccessful last-minute effort to avert the Civil War. It was proposed in Congress as a constitutional amendment in Dec., 1860, by Sen. John J. Crittenden of Kentucky with support from the National Union party. Basically, it accepted the boundary between free and slave states that had been set by the Missouri Compromise (1820-21), extended the line to California, and assured the continuation of slavery where it already existed. In addition, it advocated slavery in the District of Columbia, upheld the fugitive slave law (1850) with minor modifications, and called for vigorous suppression of the African slave trade. At a peace conference called by the Virginia legislature in 1861, the compromise gained support from four border state delegations. Nevertheless, it failed in the House of Representatives in Jan., 1861, by a vote of 113 to 80 and in the Senate in March by a vote of 20 to 19. Its defeat made clear the inevitability of the Civil War.

Compromise of 1850. The annexation of Texas to the United States and the gain of new territory by the Treaty of Guadalupe Hidalgo at the close of the Mexican War (1848) aggravated the hostility between North and South concerning the question of the extension of slavery into the territories. The antislavery forces favored the proposal made in the Wilmot Proviso to exclude slavery from all the lands acquired from Mexico. This, naturally, met with violent Southern opposition. When California sought (1849) admittance to the Union as a free state, a grave crisis threatened. Also causing friction was the conflict over the boundary claims of Texas, which extended far westward into territory claimed by the United States. In addition, the questions of the slave trade and the fugitive slave laws had long been vexing. There was some fear that, in the event of strong antislavery legislation, the Southern states might withdraw from the Union altogether.

The possibility of the disintegration of the Union was deprecated by many but was alarming to some, among them Henry Clay, who emerged from retirement to enter the Senate again. President Taylor was among those who felt that the Union was not threatened; he favored admission of California as a free state and encouragement of New Mexico to enter as a free state. These sentiments were voiced in Congress by William H. Seward. John C. Calhoun and other Southerners, particularly Jefferson Davis, maintained that the South should be given guarantees of equal position in the territories, of the execution of fugitive slave laws, and of protection against the abolitionists.

Clay proposed that a series of measures be passed as an omnibus compromise bill. Support for this plan was largely organized by Stephen A. Douglas. The measures were the admission of California as a free state; the organization of New Mexico and Utah territories without mention of slavery, the status of that institution to be determined by the territories themselves when they were ready to be admitted as states (this formula came to be known as popular sovereignty); the prohibition of the slave trade in the District of Columbia; a more stringent fugitive slave law; and the settlement of Texas boundary claims by federal payment of $10 million on the debt contracted by the Republic of Texas.

These proposals faced great opposition, but Daniel Webster greatly enhanced the chances for their acceptance by his famous speech on Mar. 7, 1850. Taylor's death and the accession of conservative Millard Fillmore to the presidency made the compromise more feasible. After long debates and failure to pass the omnibus bill, Congress passed the measures as separate bills in Sept., 1850. Many people, North and South, hailed the compromise as a final solution to the question of slavery in the territories. However, the issue reemerged in 1854 with the Kansas-Nebraska Act, and seven years later the factions were fighting the Civil War.

Breda, Compromise of, 1566: see Gueux.

(1820) Act passed by the U.S. Congress admitting Missouri to the Union as the 24th state. After the territory requested statehood without slavery restrictions, Northern congressmen tried unsuccessfully to attach amendments restricting further slaveholding. When Maine (originally part of Massachusetts) requested statehood, a compromise led by Henry Clay allowed Missouri admission as a slave state and Maine as a free state, with slavery prohibited from then on in territories north of Missouri's southern border. Clay's compromise appeared to settle the slavery-extension issue but highlighted the sectional division.

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Series of compromises in 1860–61 intended to forestall the American Civil War. Sen. John J. Crittenden proposed constitutional amendments that would reenact provisions of the Missouri Compromise and extend them to the western territories, indemnify owners of fugitive slaves whose return was prevented by antislavery elements in the North, allow a form of popular sovereignty in the territories, and protect slavery in the District of Columbia. The plan was rejected by president-elect Abraham Lincoln and narrowly defeated in the Senate.

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Series of measures passed by the U.S. Congress to settle slavery issues and avert secession. The crisis arose in late 1849 when the territory of California asked to be admitted to the Union with a constitution prohibiting slavery. The problem was complicated by the unresolved question of slavery's extension into other areas ceded by Mexico in 1848. In an attempt to satisfy pro- and antislavery forces, Sen. Henry Clay offered a series of measures that admitted California as a free state, left the question of slavery in the new territories to be settled by the local residents, and provided for the enforced return of runaway slaves and the prohibition of the slave trade in the District of Columbia. Support from Daniel Webster and Stephen A. Douglas helped ensure passage of the compromise. Moderates throughout the Union accepted the terms, which averted secession for another decade but sowed seeds of discord.

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