How did Stephen A. Douglas convey the importance of passing the Kansas- Nebraska Act

To gain the southerners' support, Douglas proposed creating two territories in the area–Kansas and Nebraska and repealing the Missouri Compromise line. The question of whether the territories would be slave or free would be left to the settlers under Douglas's principle of popular sovereignty

this isn't a question and if you're going to list things be kind and use commas.

profound political, administrative, and social changes in the british isles.