During the Lincoln – Douglas debates , Douglas articulated the Freeport Doctrine , which held that territories could effectively exclude slavery despite the Supreme Court 's ruling in the 1857 case of '' Dred Scott v. Sandford '' . Disagreements over slavery led to the bolt of Southern delegates at the 1860 Democratic National Convention . The rump convention of Northern delegates nominated Douglas for president , while Southern Democrats threw their support behind John C. Breckinridge . In the 1860 election , Lincoln and Douglas were the main candidates in the North , while most Southerners supported either Breckinridge or John Bell of the Constitutional Union Party . Campaigning throughout the country during the election , Douglas warned of the dangers of secession and urged his audiences to stay loyal to the United States . Ultimately , Lincoln 's strong support in the North led to his victory in the election . After the Battle of Fort Sumter , Douglas rallied support for the Union , but he died in June 1861
1860 Democratic National Convention
1860 Democratic National Conventions
Stephen A. Douglas