This chapter first analyses the legal functions of due diligence, notably risk-management and securing accountability, defining audits and impact assessments, or operationalising obligations of progressive realisation. The chapter interprets the rise of due diligence as a response to, a manifestation of, and a catalyst for structural change in international law. These changes include proceduralisation, pluralisation of legal subjects, de-constitutionalisation, and more proactive risk management. The chapter traces understandings of due diligence throughout the different areas of international law and across different types of legal persons. It concludes that due diligence has quite diverse meanings and functions depending on the legal context, and can therefore hardly be qualified as an overarching principle of international law. While due diligence shapes the international law of a global risk society and helps to secure accountability, it also menaces to mellow firm obligations and thus bears the risk to undermine the international rule of law.
