Stephen A. Douglas was one of the Democratic Party’s primary proponents of popular sovereignty—the concept that local voters had the right to determine whether or not to allow slavery. Douglas advocated on behalf of popular sovereignty with regard to both the Kansas-Nebraska Act and the Lecompton Constitution, the latter of which he asserted ran counter to popular sovereignty as it did not permit the Kansas Territory’s voters to disallow slavery.

Lincoln was running against Douglas in the 1858 Federal Election as the Illinois Republican Party’s candidate for the U.S. Senate. Although Lincoln had long supported protective tariffs, both he and Douglas agreed that slavery was a topic of far greater importance in the contests of 1858. During the campaign, Lincoln criticized the U.S. Supreme Court’s decision in the Dred Scott case as aiding the nationalization of slavery. For some of Lincoln’s views on popular sovereignty, the Kansas-Nebraska Act, the Lecompton Constitution, and the Dred Scott decision, see Report of Speech at Springfield, Illinois; Report of Speech at Springfield, Illinois; Fragment of A House Divided Speech at Springfield, Illinois; Report of Speech at Springfield, Illinois; Speech at Springfield, Illinois; Report of Speech at Springfield, Illinois; Report of Speech at Springfield, Illinois. See also the 1858 Illinois Republican Convention.

Ultimately, in the local elections of 1858, Republicans won a majority of all votes cast in Illinois, yet pro-Douglas Democrats retained control of the Illinois General Assembly. At the time, members of the General Assembly voted for and elected the state’s representatives in the U.S. Senate, and Douglas won reelection. Through the campaign, however, and in particular through his participation in the Lincoln-Douglas Debates, Lincoln gained recognition as well as standing within the national Republican Party.