According to the series of bills that made up the compromise, the question of slavery in the new lands acquired by the war with Mexico would be deferred. Embracing a position known as “popular sovereignty,” the voting residents of those territories would be free to take a position on slavery when they applied for statehood. Slavery would be permitted in Washington, DC, but the slave trade would be abolished within the borders of the district. Finally, California would be admitted as a free state. This new free state upset the balance in Congress between free and slave states. In order to mollify those in favor of slavery, the Fugitive Slave Act was passed.
The question of slavery would not be settled once and for all until the ratification of the Thirteenth Amendment in 1865.