A rules-based order may generally be understood as a shared commitment by States to conduct their activities in accordance with an existing set of rules.
The rules-based order is underpinned by a system of global governance that has developed since the Second World War.
The United Nations is considered to be at the heart of this rules-based order.
RBO seems to be a broader term than international law which is defined as legally binding rules that are based on, and require the consent of each individual State.
It seems to include both traditional international law rules, and what is usually referred to as “soft law” – legally non-binding political commitments.
The term “rules-based order” blurs the distinction between binding and non-binding rules, giving the impression that all States and international actors are subject to this order, irrespective of whether or not they have consented to these rules.
While international law is general and universal, the “rules-based order” seems to allow for special rules in special – sui generis – cases.