Can International Law Form Its Own General Principles?

General principles of law are the third primary source of international law, alongside treaties and customary international law. However, there is disagreement among states and scholars regarding the method by which these principles can be derived or identified. This discussion was sparked by the efforts of the International Law Commission (ILC) to examine and codify the rules on general principles of law as a source of international law. On 27 July 2026, the ILC concluded its work on the topic by adopting the draft conclusions on the second reading and submitted them to the United Nations General Assembly for consideration. Draft Conclusion 3 of the ILC states that general principles of law can not only be derived by transposition from national laws, but can also be formed directly within international law itself. States have raised several objections to this. This post examines the central criticism and aims to demonstrate that the newly formulated approach by the ILC is nonetheless convincing.

Old and New Methods of Identifying

It is generally established that deriving a general principle of law from national legal systems requires two steps: first, the principle must be common to the various national legal systems of the world; second, the principle must be transposable to the international legal system (see Separate Opinion of Judge Simma to the Application of the Interim Accord of 13 September 1995, p. 700). The ILC now formulated an alternative approach, according to which a general principle may also be formed directly within international law itself. According to the ILC, this in turn requires the principle to be ”intrinsic“ to the international legal system. To be intrinsic, the principle must be enshrined in various sources of international law and, in addition, reflect and regulate its basic features (see here, para 139). In drafting so, the ILC has likewise narrowed the scope of application for this ”second category” of general principles.

Inconsistency with the Drafting History of the ICJ Statute

In its work, the ILC bases its approach on the same understanding of ”general principles of law“ as the term is used in Article 38(1)(c) of the ICJ Statute. At this point, it should be emphasized that the term „civilized nations“ used in the Statute is anachronistic (for instance, see here, p. 133) and must rather be understood as „community of nations“ (see here, p. 14). Even though Article 38 ICJ Statute, according to its own wording, merely specifies the sources of law on which the International Court of Justice (ICJ) may base its decisions, it is generally regarded as setting forth the (non-exhaustive) catalog of sources of international law and subsidiary means of its interpretation. In this regard, some states argue that the formulated approach of general principles of law intrinsic to the international legal system is not supported by the drafting history of the Statute. Indeed, pursuant to Article 32 VCLT, preparatory work is only the appropriate means of interpretation when the ordinary meaning, context, and object and purpose of a treaty clause do not provide a sufficiently clear result of interpretation.

However, the criticism brought forward can be countered by the fact that even during the drafting process of the Statute of the Permanent Court of International Justice (PCIJ) – the predecessor of the ICJ and on which the ICJ Statute is based on (Article 92 UN Charter) – the origin of general principles of law was a matter of controversy. Ultimately, the Advisory Committee of Jurists, which was tasked with drafting the Statute of the PCIJ (including Article 38), explicitly refrained from narrowing Article 38 down to solely those principles found in national legal systems (see in-depth analysis here). This point was subsequently emphasized elsewhere by Dionisio Anzilotti, Secretary General of the Committee and later President of the PCIJ, who stated that Article 38(1) covers, first and foremost, those principles that are formed within international law itself (Dionisio Anzilotti, Cours de droit international, transl. b. G. Gidel, Paris: Sirey 1929, p. 117).

Overlap with Customary International Law

A second point of criticism is that the proposed approach of determination blurs the line between general principles of law and customary international law. It is argued that this undermines the significance of general principles of law as an independent source of law (see, for instance, the statements of the Czech Republic [p. 3], Brazil [p. 11], Israel [p. 12], the UK [p. 14], and the USA [p. 14]). This criticism becomes particularly clear when one examines the prerequisites of the method under discussion: To determine whether a general principle is intrinsic to the international legal system or not is through a comprehensive analysis of all relevant documents of international law. If one assumes that, in addition to the treaty practice of states, the practice of international organizations is also relevant for the derivation of customary international law, then one may argue a methodological similarity between customary international law and general principles of law.

However, there is already debate over whether the practice of international organizations can be relevant at all in identifying customary international law. The ILC provides for this only in certain cases (see here, p. 130 et seq). Furthermore, it should not be overlooked that even in the traditional method of identifying general principles of law, there are certain parallels to customary international law: Both the method of identifying customary international law (requiring state practice and opinio juris) and the traditional method of deriving general principles of law (requiring recognition by states and transposition to international law) begin with reference to the actions or behavior of States. Admittedly, the thresholds and specific requirements differ; however, both start – entirely in line with a purely positivist approach to international law – by focusing on the states themselves.

Additionally, one might ask whether a methodological similarity between the two sources of law is harmful to either one of them, and by that speaks against an (alternative) approach of identifying a rule of international law. Ultimately, rules of customary international law and general principles of law are, in substance, sufficiently distinct legal rules. This also becomes evident by looking at the functions that general principles of law fulfill. General principles of law serve as a „gap-filler“ in order to prevent a non liquet (see the Statement of former ICJ president Yusuf before the Sixth Committee of the UN General Assembly from 2019, para 37). A non liquet describes a situation in which no legal rule can be applied and therefore a court would have to refrain from rendering a decision. In addition, general principles of law serve as aids in interpreting other sources of law. Both functions demonstrate that, by their very nature and purpose, general principles of law are subsidiary in their applicability to treaties and customary law. In respect of this subsidiarity, the feared overlap with the derivation of customary international law does not seem particularly significant to me, especially in light of the arguments against the third point of criticism:

International Law as a Legal System vs. The Consent of States

As a third point of criticism, some states emphasize the risk that a legally binding norm could arise without their consent. This risk would be all the greater because there is no way envisaged for states to opt out of obligations arising from general principles of law, unlike in customary international law, which recognizes the concept of the persistent objector. This criticism has some merit to it; neither the ILC nor the case law of international courts support the view that a state could opt out of being bound by a general principle of law by merely lodging a protest. However, this criticism can already be weakened by again referring to the subsidiary applicability of general principles to treaty law and customary law created by states.

Ultimately, the strongest argument in favor of the ILC’s formulated second approach is that international law can be considered as a legal system on its own and not merely a collection of some rules (see Bruns, Mosler, and Peters). This means that the individual norms of international law are part of an internal regulatory framework. If this finding is to be taken seriously, and as the ILC itself notes in its Commentary on the Draft Conclusions (see here, p. 114), then international law must also be capable of forming its own general principles that are specific to it. Otherwise, it would remain structurally disadvantaged and too heavily dependent on national legal systems.

Even if one views the consent of states as the only basis for the validity of international law, this aspect remains sufficiently safeguarded by the method formulated by the ILC. The starting point for analyzing whether a principle is intrinsic to the international legal system is to examine all available sources and documents of international law: treaties, secondary law of international organizations, court decisions, etc. Of course, when a state concludes a treaty, it is primarily demonstrating its consent to be bound by that very treaty. However, this is where the threshold formulated by the ILC comes into play: a principle must be enshrined in a wide variety of sources (including treaties) from different regions of the world and (if possible) covering different subject matters in order to be considered “general”. This eliminates the risk that a state will become bound by a general principle of law as a result of concluding a single treaty. Also, secondary law of international organizations and decisions of international courts (due to their consent-based jurisdiction) can – at least to a significant extent – be traced back to the consent of states. Therefore, the criticism referring to the consent of states does not convince.

Conclusion

With the ILC having concluded its work on the topic, the Sixth Committee of the UN General Assembly will now deliberate the draft conclusions. Many states have expressed their support for the newly formulated approach; several states have taken a skeptical or generally negative stance. The key points of criticism were also recognized and taken into consideration by the Special Rapporteur on this topic Marcelo Vásquez-Bermúdez. While exercising all due caution in order to comply with the ILC’s mandate to codify and progressively develop international law, the newly formulated approach of deriving general principles of law appears to be a convincing and important step forward. The fact that international law can generate its own general principles highlights and underscores the much more fundamental observation: International law is not a fragmented collection of legal norms, but a system in which these norms are interrelated.

Special thanks are due to Elisabeth Klaes, Karl-Friedrich Stephan and Alexander Ziuber