What were the political issues that dominated u. s. politics in the 1850s?

During the 1850s, the United States of America was politically divided when democrats advocating state’s rights and the right to slavery and the Whigs who believed in strong government to protect Republican values.  Both have argued on issues of on expansion and slavery. Expansion at the time was accompanied by slavery.  As new territories were added, arguments would erupt on the issue of allowing slavery into new territories.  The Kansas-Nebraska Act eventually pushed the political divide on these issues even further.  Eventually it lead to the American Civil War.