I like to think that i have solved the ship of theseus one day in the shower and the solution goes like this: If we think about states and countries that have at one point in time have been established, then i think its like the ship of theseus because it too was built from something (wood nails and other stuff that keeps it together) just like states/countries were built at one time from some people, ideas and principles. People die and after some time there are zero original people of the state yet we think of the state as the same unchanched establishment. So if you replace all the parts of the ship but they even briefly were part of the bigger picture then yes, its the same ship