Obligation and the political authority of international law

Abstract

Why do states feel obliged to obey the rules of international law? The political elites who act in the name of states, their counterparts in international organisations and non-governmental organisations, and their ever more internationally-attuned populations all speak and act as though international law incurs real obligations. Yet existing accounts of international legal obligation suffer from the problem of ‘interiority’, in that they first ground obligation in some internal feature of the international legal system—such as sanction, consent, or discourse—but when these turn out to be insufficient they fall back on arguments about the legitimacy of the system as a whole, for which they cannot account. The roots of this problem lie in the underlying conceptions of politics that inform these accounts, and to overcome this problem I advance an alternative, ‘interstitial’ understanding politics which integrates ‘idiographic’, ‘purposive’, ‘moral’, and ‘instrumental’ forms of reason and action. This in turn allows the development of an ‘holistic’ conception of institutional rationality and an ‘anterior’ theory of international legal obligation. These innovations enable us to explain the relationship between historically grounded modes of politics and the legitimacy of particular institutional forms, including the modern system of international law. I illustrate this argument with an explanation of the logic of obligation that undergirded the international legal system of Absolutist Europe, where the legitimacy of the divine ordained political order was the primary source of obligation and fealty to God, not consent, was the salient signifier of such duty.