The Dred Scott case of 1857 was the worst decision in the history of the court. It was supposed to prevent the Civil War. Instead, it was the main factor that caused the Civil War. Chief Justice Roger B. Taney ruled that slaves could never be full citizens of the United States. Hence, the war started shortly after.
The tragedy of the Civil War was years in the coming. Of course, the culture of slavery was ingrained in the societies, both in the Northern and Southern States.
Slavery was never to be extended into the new territories or states! The framers of the Constitution were very cautious about the way they handled the slavery questions. They did not know how to present the Declaration's promise "that all men are created equal."