For as long as it suited their purposes and for as long as they could hold on to it. Are you claiming "might makes right"? because that is a POV that most Lost Causers view with disdain.
Your attempt to equate Ticonderoga with Sumter fails the sniff test. Sumters ownership was never in question right up until the rebels seized it. Although built within the boundary lines of the state of South Carolina it was ceded to the United States government in perpetuity. It was never legally the property of anyone except the USA.
It depends on whether you mean in the idealistic sense or the practical sense. From a perspective of Principle, the mighty should not impose their will on the weak just because they can. In practice, they cannot seem to help themselves.
Your attempt to equate Ticonderoga with Sumter fails the sniff test. Sumters ownership was never in question right up until the rebels seized it.
By rebels, I assume you mean the Americans who were rebelling against English rule? Totally different from the Confederates rebelling against Union rule, of course.
Although built within the boundary lines of the state of South Carolina it was ceded to the United States government in perpetuity.
It's a shame some knowledgeable lawyer didn't point this out at the time, it could have saved a lot of bloodshed. After all, if they have a legal title to the fort, how can anyone Object to their use of their own property?
It was never legally the property of anyone except the USA.
Well, I think the British Government owned it at some point. Probably for a period longer than the USA had it.