The international rules based order sets normative expectations, deters transgressions, and manages conflicts. It does so via a host of treaties and institutions mostly introduced soon after WWII, from the Universal Declaration of Human Rights to the UN and its many affiliated organisations and treaties (WTO, UNLCOS, ICJ, World Bank, NPT, etc) to private members' clubs like the G7, EU, OECD, and NATO.
Like all institutional orders, it is maintained by and for the powerful actors in whose interests it was designed, especially the USA, the most powerful of all. This obvious fact is often willfully misinterpreted.
First, an order instituted by the powerful to protect and advance their own interests need not come at the expense of the less powerful, when compared to a situation without any such order. To the contrary, by constraining all it is often of even more value to the weak - who have no other source of protection - than it is to the strong. Merely because an international order can be judged as lacking compared to some hypothetical ideal ('fairness') does not mean that any rational state would prefer a world without it.
