Freeport Doctrine was a position espoused by Democrat Stephen Douglas in a debate with Republican Abraham Lincoln in Freeport, Illinois, that territories could exclude slavery in spite of the Dred Scott decision by not enforcing any pro-slavery laws locally.
Background
Lincoln asked four questions of Douglas at the Freeport debate:[1]
Question 1. If the people of Kansas shall, by means entirely unobjectionable in all other respects, adopt a State Constitution, and ask admission into the Union under it, before they have the requisite number of inhabitants according to the English bill-some ninety-three thousand-will you vote to admit them? [Applause.]
Q. 2. Can the people of a United States Territory, in any lawful way, against the wish of any citizen of the United States, exclude slavery from its limits prior to the formation of a State Constitution? [Renewed applause.]
Q. 3. If the Supreme Court of the United States shall decide that States cannot exclude slavery from their limits, are you in favor of acquiescing in, adopting and following such decision as a rule of political action? [Loud applause.]
Q. 4. Are you in favor of acquiring additional territory, in disregard of how such acquisition may affect the nation on the slavery question? [Cries of "good," "good."]