Legal theory has long grappled with the question of what features a rule system must have for it to be considered 'law." Over time, a consensus has emerged that might seem counterintuitive to most people: a legal system does not require punishment for the disobedience of its rules (sanctions"), nor must it be obeyed by the people it purports to apply to (it need not have "efficacy'). In this Article, I do not challenge these conclusions, but instead stake out an attempt to reconcile these claims with other intuitions about law. I argue that while neither sanctions nor efficacy are alone determinative of legal validity, legal systems must at least aspire to be efficacious. Sanctions, then, may be seen as but one optional manifestation of the crucial background quality they represent: a readiness to adapt and react to the external realities surrounding a legal system's attempted implementation.
Brenner M. Fissell (Wed,) studied this question.