The Kansas – Nebraska Act divided the nation and pointed it toward civil war . Congressional Democrats suffered huge losses in the mid-term elections of 1854 , as voters provided support to a wide array of new parties opposed to the Democrats and the Kansas-Nebraska Act . By 1855 , opponents of the Kansas – Nebraska Act had coalesced into the Republican Party , which replaced the Whigs as the main opposition to the Democrats in the Northern states , although some Democratic opponents instead joined the nativist American Party . Pierce declared his full opposition to the Republican Party , decrying what he saw as its anti-southern stance , but his perceived pro-Southern actions in Kansas continued to inflame Northern anger . Partly due to the unpopularity of the Kansas – Nebraska Act , Pierce lost his bid for re-nomination at the 1856 Democratic National Convention to James Buchanan . Pierce remains the only elected president who actively sought reelection but was denied his party 's nomination for a second term . Republicans nominated John C. Frémont in the 1856 presidential election and campaigned on " Bleeding Kansas " and the unpopularity of the Kansas – Nebraska Act . Buchanan won the election , but Frémont carried a majority of the free states . Two days after Buchanan 's inauguration , Chief Justice Roger Taney delivered the '' Dred Scott '' decision , which asserted that Congress had no constitutional power to exclude slavery in the territories . Douglas continued to support the doctrine of popular sovereignty , but Buchanan insisted that Democrats respect the '' Dred Scott '' decision and its repudiation of federal interference with slavery in the territories
1856 Democratic National Convention
1856 Democratic National Convention
Kansas–Nebraska Act