This chapter examines the sources of law IATs are applying, grouping these sources into two substantially different categories: ‘self-contained’ and ‘universalizing’ sources. The self-contained sources of international administrative law are those which are specific to a given organization, including the contract of employment; the staff regulations and staff rules; the bulletins, circulars, manuals, and issuances of the organization; the constituent instrument of the organization; decisions and resolutions of the plenary organ of the organization or other decision-making body; and the practice of the organization. The chapter then examines the ‘universalizing’ sources of international administrative law, which are those sources, referred to with increasing frequency, which are ‘outward-looking’ and thus may be applied in common by multiple IATs. These include general principles of law, international law, and decisions of other international administrative tribunals, the latter to be referred to herein as ‘cross-fertilization’. As a result of these ‘universalizing’ sources, this chapter concludes that a universal law of internal justice has begun to crystalize.

This book has investigated trilogues as the democratic secret of European legislation. To this end, it has proceeded in two steps. The first step has been analytical in nature, in that it has described and reconstructed the law and practice of European legislation through a close engagement with the relevant normative sources (Chapters 1–3). The second step has been partly doctrinal and partly theoretical (Chapters 4–6). It has been doctrinal, to the extent that it has sought to capture and give distinctive meaning to “informality,” as both a key concept of EU law and an essential feature of trilogues. It has been theoretical, to the extent that it has discussed, appraised, and legitimized trilogues in the light of theories of public authority and democracy beyond the nation state. In this second step, the line of reasoning has also benefitted from a comparative chapter, which has thrown into sharper relief the advantages of a legislative process based on trilogues.