This paper analyzes the due diligence obligations with regard to transboundary harm in international water law and their application to cybersecurity by clarifying the definition of due diligence in light of the procedural duties in recent International Court of Justice (ICJ) cases. The paper explores whether states have responsibilities to prevent transboundary harm caused by nonstate actors. The existing literature on due diligence obligations in international water law and cybersecurity was reviewed, along with ICJ cases relating to procedural duties (international co-operation, environmental impact assessments, and information sharing). The findings confirm that, although procedural duties may be less onerous in cyberspace than in the environment, such duties indeed exist, albeit to a lesser degree. The differences may be accounted for by the fact that customary law related to the environment is already well developed. This study clarifies the concept of due diligence by focusing on procedural duties and examining the definition of due diligence in cyber operations. Due diligence obligations are crucial for states seeking to prevent transboundary harm and are an evolving principle of international law.
International Water Law and the Quest for Common Security