What violence erupted in kansas over slavery and in congress?

The Kansas-Nebraska Act resulted from another dispute over slvery in Congress.
Franklin Pierce, a New Hampshire Democratwho supported the Fugitive Slave Act, became president in 1853. Peirce intended to enforce the Fugitive Slave Act, and his actions hardened the opposition to slavery. Harriet Beecher Stowe's popular book Uncle Tom's Cabin added fuel to antislavery feelings with its description of slavery as a cruel and inhuman system.
In 1854 the dispute over slavery erupted in Congress again. The cause was a bill introduced by Stephen A. Douglas, the Illinois senator who had forged the Compromise of 1850. Hoping to encourage settlement of the West and open a way for a transcontinental railroad, Douglas proposed organizing the region west of Missouri and Iowa as the territories of Kansas and Nebraska. Douglass was developing a plan for the nation to expand that both the North and South would accept. Instead the bill reopened conflict about slavery in the territories.