How did President Lincoln trick the South into attacking Fort Sumter?

Historians differ as to President Lincoln's actual intentions, but his (well-publicized) decision to send a resupply fleet to Fort Sumter in April of 1861 did in fact lead the South to fire the shots that sparked the formal start of the Civil War. Lincoln's response to the fall of Ft. Sumter was aggressive and decisive in several ways: it galvanized the war effort of the North and pushed additional Southern states to secede from the Union.