what is the Freeport Doctrine? iknow it has something to do wit tha civil war?

The Freeport Doctrine was articulated by Stephen A. Douglas at the second of the Lincoln-Douglas debates on August 27, 1858, in Freeport, Illinois. Lincoln tried to force Douglas to choose between the principle of popular sovereignty proposed by the Kansas-Nebraska Act and the United States Supreme Court case of Dred Scott v. Sanford, which stated that slavery could not legally be excluded from the territories. Instead of making a direct choice, Douglas's response stated that despite the court's ruling, slavery could be prevented from any territory by the refusal of the people living in that territory to pass laws favorable to slavery. Likewise, if the people of the territory supported slavery, legislation would provide for its continued existence.