The political fallout from the passage of the Kansas-Nebraska Act in 1854, which created the territories of Kansas and Nebraska, led to the creation of the Republican Party. After the act's passage, pro-slavery and anti-slavery factions rushed into Kansas. Since the legality of slavery in the state was to be decided by popular sovereignty, violent clashes between these two groups broke out, earning the territory the nickname "Bleeding Kansas."
The failure to prevent the passage of the Kansas-Nebraska Act by the southern Whigs essentially led to the destruction of the political party. The northern Whigs hoped that other anti-slavery politicians would join them. However, the failure to maintain the Missouri Compromise and prevent the events occurring in Kansas lost the party much of its influence and credibility. Instead, anti-slavery Democrats, Free Soilers, and former Whigs formed their own party, the Republicans, in March 1854. As a unified party with a common set of goals, the new Republicans felt they would better be able to fight for their causes in government and act as a counterbalance to the Democrats.