In international law, opinio juris is the subjective element used to judge whether the practice of a state is due to a belief that it is legally obliged to do a particular act. When opinio juris exists and is consistent with nearly all state practice, customary international law emerges. Opinio juris essentially means that states must act in compliance with the norm not merely out of convenience, habit, coincidence, or political expediency, but rather out of a sense of legal obligation. →