The legislation known as the Missouri Compromise, which the U.S. Congress passed in 1820, was designed to address the issue of whether new states that permitted slavery would be admitted to the Union. Signed into law by President James Monroe, the Missouri Compromise actually embodied several compromises painstakingly worked out and often hotly debated over a period of months between the congressional representatives of states where slavery was legal and those where it was not. The most important of its provisions concerned slavery. The immediate issue was the Missouri Territory and its admission to the Union as a new state. Would it be admitted as a slave state, or should it be kept out of the Union unless it declared itself free? The larger question was whether slavery would be allowed to expand in the United States or be restricted and, in either case, how it would be done. Proslavery legislators would have preferred the unlimited admittance of new slave states. Legislators from free states wanted no expansion of slavery; many wanted it abolished in the states where it already existed.