*Party division totals are based on election day results.
As sectional interests splintered the Whig Party into irreconcilable factions, Democrats retained control of the 33rd Congress (1853–1855). The political future of the Kansas and Nebraska territories dominated House and Senate debate, and in May 1854, President Franklin Pierce signed into law the Kansas–Nebraska Act. The new legislation effectively repealed the Missouri Compromise of 1819–1820 and guaranteed the right to “popular sovereignty,” enabling voters in the territories to determine the legality of slavery. Northern Members also opposed calls by their Southern colleagues and the President to run the transcontinental railroad through the heart of the South.