Due diligence: the risky risk management tool in international law

As a standard bridging law and other spheres of normativity, due diligence is pervasive across numerous areas of international law. This paper defines the features and functions of due diligence, illustrating how the concept's development reflects structural changes in the international legal order. Concerning their content, due diligence obligations can be separated into two overlapping types: procedural obligations and obligations relating to States' institutional capacity. Thus, due diligence serves to manage risks, compensate for States' freedoms being circumscribed through legalisation, expand State accountability and possibly stabilise the international order through ‘proceduralisation’. However, it is argued that due diligence cannot be characterised as a general principle of international law due to its diverse content in different fields of international law and its dependence on accompanying primary rules. Finally, it is contended that due diligence introduces certain risks, particularly by diluting States' substantive obligations and contributing to the rise of ‘informal’ international law.