Final answer:
Stephen Douglas was willing to repeal the 36° 30' line from the Missouri Compromise to win southern votes for the Kansas-Nebraska Act.
Step-by-step explanation:
Stephen Douglas was willing to repeal the 36° 30' line from the Missouri Compromise in order to win southern votes for the Kansas-Nebraska Act. The act created two territories, Kansas and Nebraska, and applied the principle of popular sovereignty, allowing the people of these territories to decide for themselves whether to adopt slavery.