What causes of sectional conflict led to the Civil War?

the Kansas-Nebraska Act By the mid-1800s, a major issue dividing the North and South was the status of slavery in the West. “Bleeding Kansas” (1854–1858); a result of the Kansas-Nebraska Act

During this time, abolitionists (such as Frederick Douglass or Harriet Tubman) worked to oppose slavery, which angered the South. Frederick Douglass Harriet Tubman

In the 1840s, a slave named Dred Scott argued that he was legally free because he had moved to a free state with his owner. Scott’s new home (Illinois) X  X  (Missouri) Scott’s old home

Chief Justice Roger Taney The Supreme Court ruled against Scott in the 1857 case Dred Scott v. Sandford, . . . Chief Justice Roger Taney (1836–1864)

. . . deciding that slaves were property and Congress could not deprive people of their property, which angered the North. According to Dred Scott v. Sandford, the Missouri Compromise line was unconstitutional 

In 1859, abolitionist John Brown led a failed slave revolt at Harper’s Ferry and became a hero in the North, which angered the South.

Lincoln wins with less than 40% of popular vote The 1860 election of President Abraham Lincoln caused the secession of several Southern states from the Union (U.S.), which started the Civil War between the North and South. Lincoln wins with less than 40% of popular vote