Missouri Compromise: A legislative agreement passed in 1820 that aimed to maintain a balance of power by admitting Missouri as a slave state and Maine as a free state.
Compromise of 1850: Another legislative agreement that attempted to preserve the balance between slave and free states by allowing California to enter as a free state while implementing stricter fugitive slave laws.
Kansas-Nebraska Act: An act passed in 1854 that allowed residents in Kansas and Nebraska territories to decide whether they would allow slavery (popular sovereignty), effectively challenging the previously established balance of power.