The Dred Scott case was absolutely ineffective in settling the conflict over slavery. Chief Justice Taney might have thought that he was going to set the issue to rest once and for all, but he really just inflamed it. In his decision, he said that Congress had no right to legislate on the issue of slavery in the territories. This meant that there could no longer be any compromises (like the Missouri Compromise) between the North and the South on the issue of slavery. Instead, it seemed to imply that every new territory or state would have to go through the sort of violence that occurred in "Bleeding Kansas."
The Dred Scott decision also made Northerners extremely suspicious of the "slave power." It convinced them that the slaveowners of the South had the power to influence the federal government and get their way. Because the case did this and because it closed on the possibility of compromise, the decision made the conflict over slavery worse than it had been before.