Abstract
The author notes that in international law, which is a system distinct from national law, the issue of the interaction between the private and the public in law is also present, although not as prominently. It is expressed differently and rather more indirectly.
In addition to using the analogy of national law in international law, with its traditionally greater influence of private law, this issue is raised specifically in branches of international law that regulate the rights and duties of persons (natural persons or legal entities). A typical example is international investment law.
While it was created by treaties seeking to protect primarily private interests (investment and investors), and it currently includes many substantive and procedural rules, the provisions of public law play a key role in national enforcement. Their quality and correct application determine whether the conduct of state bodies and other persons, attributable to the host state, will be found to be in breach of international standards in the treatment and protection of investments, or whether it will be regarded as a reasonable regulatory measure.
The experience from international investment arbitrations indicates that it is crucial to have not only carefully drafted provisions in the treaties, but also well-written national provisions. Underestimating public law and regulation in public interest could lead to dire consequences.