Some Ways that Theories on Customary International Law Fail: A Reply to László Blutman

This brief comment seeks to clarify a foundational concept inherent in any discussion of customary international law (CIL): consent. Any serious attempt to construct a coherent theory of CIL must resolve the fundamental tension between non-consensual rulemaking and international law's formal commitment to the principle of consent. As a matter of observation, states rarely accept non-consensual laws or external norms as binding. Yet it is also undeniable that CIL serves and persists as a fundamental building block of international law. Therefore, in order to coherently theorize CIL, we must - at the very least - provide a plausible explanation for why rationally self-interested states would take CIL and other non-consensual laws seriously.