The Intent of The Framers -- Part II -- Dred Scott
The Supreme Court in Dred Scott said that Congress had no right to ban slavery in the territories that were not yet states. (In the case of Dred Scott it was Wisconsin, but as a political matter, Wisconsin was really a stand-in for Kansas and Nebraska and New Mexico. Nebraska and New Mexico both being much larger then than now.)
Until Dred Scott, Congress assumed that it had the power to regulate slavery in the territories before they became states, and exercised that power from the Northwest Ordinance in 1787 through to the Kansas-Nebraska Act in 1854. Congress, and everybody else, knew that its use of this power would pre-determine which way the newly admitted state would decide the slavery issue. That is why the Dred Scott court was so determined to limit Congressional power.
Commenting on the implications of Dred Scott was the topic of much of Abraham Lincoln's political activities in those days. Lincoln's "House Divided" speech, for example, talks about the conspiracy to rebuild the house. Lincoln imagined a Dred Scott II type of decision that would require every state to accept slavery. That was a pretty paranoid charge. Still, Lincoln gained a lot of support by saying those things. The Supreme Court's silence, and what it might do next, also came up a lot in the Lincoln - Douglas debates.
And Lincoln's Cooper Union speech was an attempt, through statistical analysis, to show that the 39 men who were both at the Constitutional Convention and who served in Congress, firmly believed in the right of Congress to limit slavery in the territories and were not in favor of slavery as anything other than a short-term resolution. Lincoln would refer to it as "putting slavery on the road to ultimate extinction" According to Lincoln, back in the time of the Framers, even the Southern Framers were in favor of limiting slavery.