 Just as it is controversial whether international law is truly law, some have also raised doubts as to whether international law should be assessed in terms of the “right to rule” asserted by states. A lot of international law takes the form of treaties that bind only states that are parties to them. It might seem that the idea of a promise or contract, rather than that of legitimate rule, is the right template for assessing the normative force of such treaties. Moreover, the other main source of international law, customary international law, being the product of the convergent practice and attitudes of disparate state actors, does not assert a right to rule in the way that a unitary ruler, whether an individual or group, such as a legislative body, does. Yet others have claimed that, insofar as we can impute a claim to rule to international law, it is not as strong as that made by states, but amounts instead to a claim of the existence of a moral reason for maintaining and conforming to international law, not in a content-independent moral obligation (Buchanan 2013).