Appearently the Harriet Lane arrived off of Charleston Harbor prior to the arrival of the Nashville. Was the Harriet Lane establishing a blockade of the Harbor at that time? Why did the Harriet Lane fire on the Nashville?
I know that the Harriet Lane was a revenue cutter to collect the taxes on imports. But she was also a part of a task Force sent to relieve the garrison at Fort Sumter. If you say that tax collection was her purpose in firing on the Nashville, then why hadn't that tax collection been going on in the 3 months prior to the Nashville incident? If the Harriet Lane was acting as part of her duties of the Task Force then she was committing an Act of War against the Confederate States.
What I am saying is that the effective naval blockading of a nations ports is an Act of War under International Law. Let alone the firing upon a ship in open waters. All well before there was ever a "First" shot fired at Fort Sumter.