Which legislative acts pertained to the balance of slave and free states as new states were added?

The Missouri Compromise and the Kansas-Nebraska Act are significant legislative acts that addressed the balance of power between slave and free states during the expansion of the United States.

The Missouri Compromise, enacted in 1820, was crucial because it established a line of demarcation at latitude 36°30' north, separating free and slave territories. When Missouri was admitted as a slave state, this act allowed Maine to enter as a free state, thus maintaining the balance in Congress. It aimed to alleviate tensions by creating clear geographical boundaries for the expansion of slavery.

The Kansas-Nebraska Act, passed in 1854, further influenced this balance by allowing the territories of Kansas and Nebraska to decide for themselves whether to allow slavery via popular sovereignty. This act effectively repealed the Missouri Compromise line's significance, igniting fierce conflicts known as "Bleeding Kansas." Both acts were pivotal in shaping the political landscape surrounding the issue of slavery as new states joined the Union, illustrating the ongoing struggle to maintain equilibrium between slave and free states.

While other acts and plans, like the Virginia Plan or debates such as those between Lincoln and Douglas, played essential roles in American history, they did not specifically address the balance of slave and free states in the