The federal government is simply a creation of the states. The states are the contracting parties. Besides massive cessions of land (Nortwest Territory, Tennesee, Alabama etc) to create new states, Southern blood and monies were paid to acquire new territories. Northern states wanted to have the territories for whites only (not that there would ever be a mad rush for blacks to emigrate west - there were few in territories) - and attempted to deprive Southerners of the equal participation in settlement of the territories.
Nowhere in the Constitution does it deny a state, or group of states, access to property in common. Specifically Article 9 §1 grants Congress the power to deny emigration in states 'now existing', not any future expansion.
The federal government was also charged to 'insure domestic Tranquility', yet did nothing to rein in insane Northerners hell bent on destroying Southerners and the union. Mass murderers (John Brown and his men) were financed by yankees, but not prosecuted - instead they were editorialized as martyrs. Brown and his men marched their victims to a clearing, and with swords split open the head of James Doyle, and then proceeded to sever the arms of his son Drury, and killed his other son Willaim. Brown and his murderous minions then slaughtered Allen Wilkinson in front of his wife and children, and lastly murdered William Sherman.
One socialist, Julia Ward Howe, later memorialized the actions of Brown in song and his 'terrible, swift sword' Most don't realize it, but it's to the tune "John Brown's Body", so with each rendition, a mass murderer is being glorified.
Lastly, several of the states seceded AFTER Licoln demanded troops from those states to be used to invade the seceded states. The Constitution does not require states to enumerate their actions, nor does it prohibit secession. The convention did vote down (twice) the use of force against a state.
I think the best course for the deep South interests would be to unite with the Douglas wing of the Democratic party. Douglas would have given them everything they could have wanted except virulent support for the expansion of the slave empire. But they loved their peculiar institution and wanted all or nothing. They apparently saw the Union as worthless if it didn't give them everything they wanted. It's a shame the secessionist tail wagged the dog.
Whatever Lincoln did later would have been moot had the hotheads not had their disastrous temper tantrum.