The Compromise of 1850 was a congressional attempt to resolve differences over slavery that arose as a result of the Mexican War and threatened the precarious balance of free and slave states created by the Missouri Compromise of 1820. With the end of the war in 1848, the United States acquired a large amount of land in the west from Mexico. The Missouri Compromise had determined how slavery would be dealt with in territories formed out of the Louisiana Purchase of 1803, but, the Mexican cession brought more than one-half million square miles of new land in the country. An attempt to extend to the Pacific Ocean the Missouri Compromise 36° 30’ parallel line, above which slavery was prohibited, failed. Sen. Henry Clay offered proposals for compromise that formed the basis for the final legislation.
The Compromise of 1850 consisted of five bills that became law in September 1850. In the first act, California was admitted to the Union as a free state. Texas agreed to cede its claim for western lands, and the territories of New Mexico and Utah were formed without reference to slavery, thus allowing for popular sovereignty. The slave trade was ended in the District of Columbia. Finally, in one of its most controversial elements, a new fugitive slave law was passed that strengthened existing legislation to the benefit of slavery proponents and outrage of opponents of slavery in the North.
Hamilton, Holman. Prologue to Conflict: The Crisis and the Compromise of 1850. Lexington: University Press of Kentucky, with a new introduction by Michael F. Holt, 2005. Originally published 1964.