John G. Nicolay, The Outbreak of Rebellion

[20] For this extraordinary state paper, which effectually tied the hands of the administration and opened to rebellion a pathway free from obstruction or danger, the trio of conspirators in the Cabinet, Cobb, Floyd, and Thompson, may be reasonably held responsible. How they beguiled a President of waning mental powers and naturally feeble purpose, may be easily enough imagined; but how they silenced the honest logic of their loyal colleagues, is yet one of the riddles of history.

The first and chief solicitude of the South Carolinians was to gain possession of the Charleston forts. To secede, to organize their little State into a miniature republic, was indeed a vast achievement in their own eyes; but they were shrewd enough to perceive that their claim to independence and sovereignty would be ridiculed by the family of nations if they could not control their own and only seaport. That alone would give them a free highway to the world at large; with that they could offer the benefits of commerce, security from tempests, refuge from the perils of war, to ships of other nations; could negotiate advantageous treaties, and perhaps conclude powerful alliances. “We must have the forts” was therefore the watchword of the secret caucus; and before long, from every street-corner in Charleston, came the impatient echo, “The forts must be ours.”

The city of Charleston lies on a tongue of land between the Ashley and Cooper rivers; from their confluence the bay extends eastward some four miles to the open sea. Three forts defend the harbor. The first and smallest is Castle Pinckney, an old-time structure of brick, and of insignificant strength in modern warfare. It lies one mile from the city; it was capable of holding a war garrison of 100 men; and its armament of twenty-two guns was at the time complete. Farther out is the second in size and importance