Politics and law have long been seen as separate domains of international relations, as realms of action with their own distinctive rationalities and consequences. So pervasive is this view that the disciplines of International Relations and International Law have evolved as parallel yet carefully quarantined fields of inquiry, each with its own account of distinctiveness and autonomy. Hans Morgenthau famously asserted that the political realist ‘thinks in terms of interest defined as power, as the economist thinks in terms of interest defined as wealth; the lawyer, of conformity of action with legal rules; the moralist, of conformity of action with moral principles’. Curiously, many scholars of international law have acquiesced in this separation. With notable exceptions, international law has been presented as a regulatory regime, external to the cut and thrust of international politics, a framework of rules and institutional practices intended to constrain and moderate political action. Legal philosophers have frequently sought to quarantine law from politics for fear that the intrusion of politics would undermine the distinctive character of law as an impartial system of rules. From both sides of the divide, therefore, international politics and law have been treated as categorically distinct, and while international law was given little space in the international relations curriculum, students of international law have learnt doctrine and process but not politics.

To many observers of contemporary international relations, this neat separation of politics and law seems increasingly anachronistic.