They aren't that connected. It's a loose affiliation.

Even then, it's only when they agree. If the Italians liked him he would likely have been protected.

They aren't. The US is just in a unique position where its projected force in most of the world is sufficient to make other governments mostly do what they want without them having to even say it.

Of course the US is also apparently trying to change that at the moment by speedrunning an era of self-humiliation and wiping out its economic influence and "soft power" over the mistaken belief that you can strong-arm international negotiations with military power alone in the Atomic Age.

> unpopular opinion, but what is the point of having borders, countries and legal systems if they are all connected into one global unit giving merely an illusion of separation to groups of people?

You didn't state an opinion (unpopular or otherwise), you asked a question.

But the question is very much like asking why have defined property rights, property lines, fences, etc., when people still engage in voluntary trade and other interactions.