How did Lincoln approach the situation at fort Sumter?

On March,29, 1861, Lincoln ordered to set up a naval task force to supply the fort with provisions for a year and introduce 200 men to reinforce the garrison. On April 7 the expedition weighed anchor.

At the same time he sent a messenger to Charleston who presented to the Governor Pickens a confidential letter, in which he said that food supplies would be introduced in the fort. If he had not met resistance, it would not make any attempt to introduce weapons, ammunition and reinforcements without notifying the governor.

The Confederates reacted isolating the fort and preventing the garrison from receiving both post and provisions.

On Apr. 10, 1861, the Confederate Secretary of War cabled to Gen. Beauregard, ordering him to ask the surrendering of Fort Sumter.