“A legal system exists,” Joseph Raz claims, “if and only if it is in force.” By this he means to suggest that the efficacy of law—that is, its capacity to control the population to which it applies—is necessary for its identity as such. Despite widespread recognition that efficacy is a condition of the existence of law, however, little time has been spent analyzing the notion. This article begins an attempt to make up the deficit. I make the case for efficacy as necessary for law and go on to develop and defend an account of the concept that is broadly Kelsenian in spirit. In doing so I address questions concerning the relationship between obedience and enforcement in an account of the existence of a legal system as well as relating the discussion to that concerning the ontological status of international law.

中文翻译：

---

功效条件

“法律体系存在，”约瑟夫·拉兹声称，“当且仅当它生效时。” 他的意思是说，法律的效力——即它控制它所适用的人群的能力——对于它的身份本身来说是必要的。尽管人们普遍承认效力是法律存在的一个条件，但是，很少有人花时间分析这个概念。本文开始尝试弥补赤字。我将效力的理由作为法律的必要条件，并继续发展和捍卫对在精神上广泛具有凯尔森主义的概念的解释。在此过程中，我根据法律体系的存在来解决有关服从和执行之间关系的问题，并将讨论与有关国际法本体论地位的讨论联系起来。