That is not the impression Buchanan gives in his letter to the rebel commissioners. In fact he denies that he sent any such letter to Anderson because before he could word came that the other federal facilities had been seized by South Carolina, and as far as Buchanan was concerned that was a violation of the agreement in and of itself. And I'm aware of no letter from Buchanan to Anderson included in the OR. What does Klein give as his source?
Governor Pickens had demanded in a letter to Buchanan that state troops be placed in Fort Sumter. This was before Anderson moved to Sumter. Buchanan offered the 'status quo in the forts' agreement to forestall Pickens. Anderson later violated that by moving to Sumter.
That was not Buchanan's understanding. His position was that he agreed that he would not try to reinforce the garrison in Charleston so long as they were not attacked. Nor would he order any changes in the disposition of the forces, and he did not. Anderson acted under his own authority to safeguard his command, as he was authorized to do. Buchanan refused to second guess him, especially once it was clear that there was no post that Buchanan could order Anderson back to.
Buchanan dictated it, and "A compliant Floyd signed the message, and it was sent by courier to Anderson." (page 149, Klein)
I'm in and out this afternoon. I'm cooking some skirt steak slowly on the grill for a family fajita dinner tonight, and I'm trying to wrap up the inventory for my mother's estate, which I am badly behind on. So I'll be off the thread for a few hours.