[BroJoeK]

"Position of Fort Sumpter from a Military Point of View – 6"

Here the letter writer, named Miles, urges evacuation of Fort Sumter on grounds of military necessity, further noting the fort was never fully "occupied" and never "commanded" its position, but was instead nothing more than a military barracks.
So evacuation in the face of military necessity should be in "good grace".

Nowhere does this writer, or any other, argue that Confederates have a lawful right to claim Fort Sumter and that's why the Union should abandon it.

[Homer_J_Simpson]

I've never been to Fort Sumter, but the picture of it in this week's Harper's Weekly make it look pretty solid for nothing more than a military barracks.