[BroJoeK]

rustbucket quoting Defiance: "The mounting pressure to act dismayed Lincoln.
He had struggled to keep the door open for Seward's policy of delay as long as possible."

That's the important point.
Lincoln's policy then was to delay and delay as long as possible, in hopes (futile as it turned out) that Southern Unionists would exert pressure on Confederates to rejoin the Union.

In the mean time, he intended to hold onto those few Federal properties still under Union control -- Sumter and Pickens.
But there was no way to hold Sumter beyond April 15 without resupplying it, and so that's what Lincoln attempted, and notified South Carolina Governor Pickens on, April 6.

[rustbucket]

I am very busy with other stuff, but I am honor bound to correct some of your errors.

But there was no way to hold Sumter beyond April 15 without resupplying it, and so that's what Lincoln attempted, and notified South Carolina Governor Pickens on, April 6.

I hope you aren't still using that discredited almanac you've used before for "facts" about the war. April 6? Try this online source: April 8

Oh, and why on March 5, the day after his inauguration, did Lincoln secretly start trying to reinforce Fort Pickens and break the truce without informing the other side, possibly beginning the war there like Adams and Meigs said? Was Fort Pickens running out of food like Sumter?