In the period between Lincoln's election in November and his inauguration in March, the Union disintegrated. On November 9, three short days after Lincoln's election, a secession convention was called in South Carolina. Although no definitive action was taken, South Carolina's senators resigned from Congress the next day. In the following weeks, several southern states would consider seriously the possibility of leaving the union.
In December, President Buchanan made his final address to Congress. As a lame duck, Buchanan took a characteristically pasty stance, calling secession illegal but also failing to recognize the Federal government's capacity to prevent such action. With his administration winding down and sectional conflict heating up, Buchanan began to lose the members of his cabinet one by one. On December 8, Secretary of Treasury Howell Cobb of Georgia presented his resignation, indicating his view that secession was a necessary step for the southern states. Less than a week later, Secretary of State Lewis Cass of Michigan would also resign, but for very different reasons, feeling that Buchanan was not taking a strong enough stand against the threat of secession.
Finally, on December 20, 1860, against the best efforts of President Buchanan to the contrary, South Carolina officially seceded from the Union. As the home state of the late John C. Calhoun, champion of nullification, South Carolina had tested the constitutional basis of union before, but it had never stepped quite this far into the unknown. Implausible and unlikely as it might have seemed, the United States had become two nations.
In a last desperate attempt to preserve what remained of the Union, and to bring South Carolina back into the fold, Senator John J. Crittenden of Kentucky attempted to follow in the steps of his fellow statesman Clay with a compromise that would be amenable to all sides. His proposal provided for the restoration of the boundary drawn under the Missouri Compromise, an even stricter fugitive slave law, federal compensation for owners of runaway slaves, and territorial entry into the Union on the basis of popular sovereignty. In addition, a congressional proviso would prevent the Constitution from being amended in such as to prohibit slavery in states where it already existed.
The Crittenden Compromise enjoyed considerable support, but in the end it was Lincoln who rejected it as untenable. Satisfied though he was with the idea of guaranteeing the right of slavery in states where it existed, Lincoln insisted that the government could "entertain no proposition for a compromise in regard to the extension of slavery." Crittenden would suffer as much as any in this final failure to reach middle ground: one of his sons remained with the Union in the Civil War while the other defected to the Confederacy.
With an insurgent state government in his midst, President Buchanan was faced with a crisis in the closing days of his administration. In attempt to cut their losses in truant South Carolina, federal agents had bolstered their position at Fort Sumter in Charleston Harbor on December 26. Reasserting independence from the federal government, South Carolina demanded a total evacuation of the harbor. Buchanan refused to comply, and sent a ship full of reinforcements and supplies down to Charleston a few days later. With this act, Buchanan lost the remainder of his cabinet, which had been liquidated completely in less than a month.