This article takes as its starting point the failure of the so-called normativewing of the English School to theorise the foundational determinants of valuefrom which international society derives its normative character. In otherwords, they have not adequately thought through ‘the law behind thelaw’; that is, the underlying basis of obligation in internationallife. Thus, English School theorists are able to describe and to explain variousnorms but they cannot make sense of the reasons why any of these norms should beregarded as obligatory. Failure in this regard is attributable in large part tothe way in which pluralist and solidarist conceptions of international life aretypically understood as representing conflicting moral claims. This articleseeks to move beyond these seemingly incommensurable claims, and the debate towhich they give their names, by putting forward an account of obligation thatreconciles the unity of human community and the freedom of international societyin a single, intellectually coherent argument. The article concludes by arguingthat a normative version of English School theory formulated in this way opensspace for thinking through much of what still confounds the English School,including the normative character of political economy, the existence of arational order of values, and the ever elusive meaning of world society.