I don't think it's necessarily false equivalence to say that if you assume a group of states can be bound in the same [legal, financial and political] ways that

I don't think it's necessarily false equivalence to say that if you assume a group of states can be bound in the same [legal, financial and political] ways that a single state is. I get that it's a near-identical variant of the argument you're making, but you have an unstated assumption that effective supra-national political (or otherwise) systems cannot exist. The Five Eyes is an example to the contrary. ASEAN is another in a more economic vein. These examples shown it's possible to achieve a balance between respecting national sovereignty and avoiding inter-state armed conflict. We could probably use more of them these days, global trends notwithstanding.