Giles Distinguished Professor Emeritus of history at Mississippi State University
Preserving the Union meant doing what it took to prevent its dismemberment. Fort Sumter became the symbol of the ability or inability of the national government to maintain control over its territory, and the ability or inability of the Confederates to eject Federals from what they considered to be their land. Lincoln knew he had to hold on to that fort or admit the success of Confederate secession and the dissolution of the Union. Jefferson Davis and the Confederates believed just the opposite.
Ironically, both Lincoln and Jefferson Davis hoped that the other side would go on the attack first and thus lose the moral high ground. Lincoln held fast, but the Confederacy blinked and Southern cannon opened fire on Fort Sumter.
Did Lincoln’s actions to preserve the Union maneuver the Confederates into going on the attack first? Historian Charles Ramsdell certainly thought so in his famous Journal of Southern History essay in 1937. This was hardly the case, however. Southerners were only too happy to attack the fort on their own. Had Lincoln tried to resupply Sumter or not, it seems probable that the South would have attacked anyway. The Confederacy had gone too far already in its determination to be a separate nation to do anything less.