“...it wasn’t until CSA attacked a small island that the US Navy had literally built that war commenced...” [ctdonath2, post 74]
You are mistaken about the origins and organizational control of Ft Sumter in Charleston Harbor.
From before the American War of Independence until 1947, coast & harbor defenses of the United States were the responsibility of the War Dept. They were built, maintained, manned & operated by US Army personnel; after the War Dept was inactivated in 1947 they remained under control of the Army Dept until the Coast Artillery was itself inactivated in 1949.
In a twist of irony, in April 1861 Ft Sumter was under the command of Robert Anderson (USMA 1825), a Kentucky native who chose to remain in the Union Army instead of resigning to join the Confederacy.
The referenced website is a major inline resource for students & scholars of coast defense history.
While they existed, US coast defenses were the chief mission and activity of the US Army during peacetime. Much of the work of the Army Corps of Engineers was devoted to construction and maintenance - a task lasting generations. Coast artillerists worked never-endingly with the Ordnance establishment to develop better guns, projectiles, and propellants - an endeavor that took on increased importance with the invention of better materials and nitro (smokeless) powders in the waning years of the 19th century.
Meshing electrical power with telephone communications, mechanized range-finding, and mathematical prediction of trajectories, coast artillery became the high-tech branch of the Army.
In further ironic twists, seacoast defenses of the continental United States never came under major attack by hostile forces from the sea.
Ok, so it was US Army instead of US Navy which literally built the very ground which Ft Sumter stands on.
Doesn’t change my view that the Civil War started because South tried to take land which North owned by creation, not simply possession. “I made this” matters.