The history of constitutional crises up to the Civil War is a succession of disputes over slavery:

 

  1. Traditional balancing (represented in the 1860 election by Constitutional Union Party): Congress had full power to permit or prohibit slavery in the territories, as it had in the Northwest Ordinance, the southern expansion, and the Missouri Compromise. But the traditional balancing of slave against free territories was itself a constitutional principle. Crittenden (Dec 1860) proposed an irrepealable constitutional amendment to codify this.
  2. "Free soil" (Republicans): answered the territorial power question in the same way, but advocated ending the policy of extending slavery into any future territories (starting with the Wilmot Proviso). In fact, they interpreted the "due process" clause of the Fifth Amendment to mean that it could not extend slavery to anyplace where it did not already exist.
  3. "Popular sovereignty" (Northern Democrats): argued that every community had the right to determine the question for itself, be it a territorial government or a state government. Congress, they said, could create a territorial government having this power, but could not itself exercise the power. In holding this, Douglas et al. blithely ignored the Northwest Ordinance.
  4. States' rights (Southern Democrats): answered with the theory of state sovereignty. States, and only states, have the power to make policy concerning slavery. Citizens of a state migrating to an organized or unorganized territory had their property rights protected according to the law of their state. The federal government had to assist in this protection. Hence neither territorial governments nor Congress could prohibit slavery in territory that was not yet a state.