Supranationalism: The Modern Empire

I am trying to determine if supranationalism is a relatively new development in the history of man or if it is an old concept that has been influencing international relations for centuries. Obviously NATO and the Warsaw pact are prime examples of a very unique form of supranationalism which arose in the past century but they seem to me faint reflections of an even older idea. I'm thinking of empires, the Roman Empire for example. The Roman Empire was a multinational cohesive identity useful in deterring military aggression or ensuring greater economic security. There were smaller independent nations that identified with or allied with the Roman Empire, or they were "part" of the Roman Empire, and this afforded them an added level of security and prosperity, to a point. Quite similarly this seems to be the point of supranationalism in all its modern manifestations. Smaller independent nations can affiliate with a larger supranationalistic organization to ensure their security and prosperity. In a way supranationalism in the world today is similar to what an Empire used to be. Of course there is often an overlap between different "Empires" for example NATO and the British Commonwealth share many of the same members. Either way supranationalism is usually an excellent deterrent of military aggression as well as a promoter of economic stability.

This isn't always the case though and it seems supranationalism can actually instigate military action when it comes to smaller nations. If I were a small country for example and I was partnered in a military alliance with large powerful countries, I wouldn't be too reluctant goad my enemies. I could be a hardliner in negotiations, I wouldn't have to give into their demands, sure they may resort to military actions but that is alright, I have the US on my side.