1. Lincoln-Douglas Debates Presentation created by Robert Martinez Primary Content Source: America’s History Images as cited.

2. Abandoning the Whig Party in favor of the Republicans, Lincoln quickly emerged as their leader in Illinois. abelincoln.com

3. Campaigning for the U.S. Senate against Stephen Douglas in 1858, Lincoln alerted his audiences to the dangers of the Slave Power. wikihistoria.wikispaces.com

4. Lincoln warned that the proslavery Supreme Court might soon declare that the Constitution “does not permit a state to exclude slavery from its limits,” just as it had decided in Dred Scott that “neither Congress nor the territorial legislature can do it.” quotesofabrahamlincoln.blogspot.com

5. In that event, Lincoln continued, “we shall awake to the reality… that the Supreme Court has made Illinois a slave state.” art.com

6. The prospect of slavery spreading into the North resonated in Lincoln’s famous “House Divided” speech. Quoting from the Bible, “A house divided against itself cannot stand…” en.wikipedia.org

7. Lincoln predicted a crisis: “I believe this government cannot endure permanently half slave and half free….It will become all one thing, or all the other.” mrkash.com

8. The contest in Illinois attracted national interest because of Douglas’s prominence in the Democratic Party and Lincoln’s reputation as a formidable speaker. kids.britannica.com

9. During a series of seven debates, Douglas declared his support for white supremacy: “This government was made by our fathers, by white men for the benefit of white men and their posterity forever,” he asserted, and he attacked Lincoln for supporting “negro equality.” griffinelection.wordpress.com

10. Put on the defensive by Douglas’s racial rhetoric, Lincoln advocated economic opportunity for free blacks but not equal political rights. smithsonianmag.com

11. Lincoln asked how Douglas could accept the decision in Dred Scott (which protected slave owner’s property in the territories) and yet advocate popular sovereignty (which asserted settlers’ power to exclude slavery.) historyonair.com

12. Douglas responded with the so-called Freeport Doctrine, which suggested that a territory’s residents could exclude slavery simply by not adopting a law to protect it. uselectionatlas.org

13. Although that doctrine pleased neither proslavery advocates nor abolitionists, the Democrats won a narrow victory over the Republicans in Illinois, and the state legislature reelected Stephen Douglas to the U.S. Senate. history1800s.about.com