This Act consisted of the area Nebraska which wasn't claimed by anyone and it violated the Missouri Compromise. which could have led to war because that then caused separation between the North and the South.
Dred Scott Decision(1857)
Prohibited the North from hiding run-away slaves and required Northerners to send them back to slaves. This could have led to war because it totally goes against the morals and opinions of Northern settlers.
In 1854 a Pro-Slavery Candidate was elected into Congress. Which could have led to war because people already had already chose whether or not they were for or against slavery.
The Election of 1860
Dred Scott a slave brought to the Supreme Court that he was a free man because he was in free territory with his master. Could have caused war because it defied the rights given to him in the constitution.
This debate was about slavery which was between Lincoln and Douglas. This could have caused war because it was drawing a farther wedge between the North and South.
Stephen Douglas a Northern Democrat was elected as president. This could have caused was because he based his actions off of popular sovereignty.