Delivered in Springfield, Illinois, after Lincoln accepted the Republican nomination for the US Senate in 1858, the speech argues that the country cannot remain permanently divided between slave and free states. Lincoln does not predict the immediate collapse of the Union, but says the conflict must eventually be resolved in favour of either slavery’s containment and decline or its wider legal acceptance.

He examines the Kansas-Nebraska Act, popular sovereignty and the Supreme Court’s Dred Scott decision, presenting them as connected developments that could make slavery lawful throughout the United States. Lincoln questions Stephen A. Douglas’s professed neutrality on whether slavery should be permitted in new territories and argues that such indifference assists its expansion.

The speech concludes with a call for Republicans to remain united and rely on committed opponents of slavery. Lincoln acknowledges that political errors may delay their cause, but expresses confidence that sustained resistance will ultimately succeed.