1818年，「密蘇里領地」（Missouri Territory）向國會提出申請，欲成為 聯邦正式一州，但此升格案卻在國會審議過程中引發軒然大波。北方國會 議員在密蘇里升格案中附加但書，要求密蘇里在升格前，必須放棄已在當 地行之多年的奴隸制度。北方此舉立刻引發南方各州強烈反彈，南方國會 議員強調，奴隸制度既受《美國憲法》規範，斷不得由國會逕行廢止，而 憲法亦未授予國會此項權力。「密蘇里協議」（Missouri Compromise）的整 起過程，凸顯了奴隸制度在美國社會的複雜性，以及解決此問題的難度。 其主要癥結之一，是在現行的政治架構下，國會究竟有無權力禁止地方蓄 奴，甚至直接宣告廢止奴隸制度。「密蘇里領地」是否能成為聯邦正式一 州，在歷經三年的國會激烈辯論後，終於塵埃落定。1820 年3 月，南北國 會議員終於就密蘇里加入聯邦一事達成共識， 史稱「密蘇里協議」或 「1820年協議」（Compromise of 1820）。

In 1818, after the Missouri Territory applied for statehood, several congressmen representing the North argued that Congress could not approve of the application until Missouri abolished slavery, an institution that had existed in Missouri before it became a territory of the United States in 1803. Congressmen representing the South, however, opposed the motion, arguing that slavery was an institution protected by the constitution. The conflict between the North and South on the issue of Missouri became “the most portentous one which ever yet threatened our Union,” as Thomas Jefferson wrote in 1820. The Missouri controversy exposed the complexity of slavery in American society and intensified the struggle between pro-slavery and anti-slavery forces. After a series of congressional debates and negotiations, a final agreement was finally reached in 1821 allowing Missouri to be admitted to the Union as a slave state. This article examines congressional records from 1818 to 1821 to explore the myths and facts surrounding Missouri’s controversial application for statehood. It examines major arguments used by northern and southern congressmen on the Missouri question, and in the process reveals the underlying forces that shaped the compromises of 1820 and 1821.