1. Fugitive Slave Act: Both the Compromise of 1850 and the Kansas-Nebraska Act included provisions reinforcing the Fugitive Slave Act of 1793, making it more difficult for enslaved people to escape and find freedom. This was seen as a significant gain for the South, as it helped to maintain their institution of slavery.
2. New Territories: The Compromise of 1850 added New Mexico and Utah as new territories, potentially open to slavery based on popular sovereignty. The Kansas-Nebraska Act further extended this principle by establishing the Kansas and Nebraska territories with the intention of allowing their residents to decide on the issue of slavery through popular vote. This potentially provided opportunities for the expansion of slavery into these new territories.
3. Balance of Power in Senate: The Compromise of 1850 and the Kansas-Nebraska Act helped maintain a balance of power between free and slave states in the Senate. By adding New Mexico, Utah, Kansas, and Nebraska as territories or states, the South ensured that its representation in the Senate would not be significantly diluted, preserving their influence in the federal government.
4. Reopening of Slave Trade: The Kansas-Nebraska Act repealed the Missouri Compromise of 1820, which had prohibited slavery north of the 36°30' parallel. This opened up the possibility of extending slavery into the newly created Kansas and Nebraska territories. While slavery was not ultimately established in these territories, the South saw the repeal of the Missouri Compromise as a victory for their cause.
Overall, the South gained additional protections for the institution of slavery, new opportunities for its expansion, and maintained its political power through these legislative acts.