The ability to project power and protect property / territory is essential to sovereignty. History has been ruled by those who can project power onto those who can’t. Mutually assured destruction is the only thing that’s worked between superpowers.

When a city state can content with a nation state in the game of power projection (and/or guaranteed defense from these powerful institutions), then it can can be sovereign. It is the critical step.

Technology is getting to a point whereby it may become attainable for much smaller groups to match much larger institutions in these games. Hopefully there is a breakthrough soon and I would prefer it to be a defensive breakthrough.