Author: Juan Inoriza
Date: 20 July 2025
1. Sources of Public International Law
Public International Law (PIL) is founded upon a system of sources that define and articulate the conduct of States and other international actors. The principal sources are enumerated in Article 38(1) of the Statute of the International Court of Justice (ICJ), which lists international treaties, customary international law, general principles of law recognised by civilised nations, as well as judicial decisions and doctrine as subsidiary means for determining rules.[1]
International treaties, such as the Rome Statute (1998) or the Vienna Convention on the Law of Treaties (1969), are binding agreements reflecting the will of States. Customary international law, shaped by general practice and opinio juris, is crucial in areas such as the law of the sea or sovereign immunity.[2]
A fundamental concept is ius cogens, i.e., the peremptory norms of international law which admit no derogation, such as the prohibitions of aggression, genocide, slavery, or torture. The existence of these norms reinforces the idea that PIL embodies fundamental values, and violations entail international responsibility for States.[3]
The evolution of the law of the sea illustrates the adaptability of PIL: from the traditional three-nautical-mile sovereignty rule, it has expanded to the 200-nautical-mile Exclusive Economic Zone (EEZ) as defined in the Montego Bay Convention (1982), granting rights of resource exploration and exploitation.[4]
2. Subjects: States, Individuals, Organisations
PIL primarily recognises States as full subjects, possessing international legal personality, sovereignty, and treaty-making capacity.[5] However, the development of international law has incorporated new actors:
- Individuals, who can be held responsible for international crimes (genocide, war crimes, crimes against humanity) before tribunals such as the International Criminal Court (ICC).[6]
- International organisations, such as the UN, the EU, or the African Union, which hold normative and executive powers.
- National liberation movements and multinational corporations, which, although not full subjects, exert significant influence in fields such as investment law and human rights.[7]
3. State Responsibility and Compliance
The international responsibility of States arises when an act or omission breaches an international norm. The principal legal framework is the 2001 Draft Articles on Responsibility of States for Internationally Wrongful Acts adopted by the International Law Commission (ILC).[8]
- A clear example is the Russian invasion of Ukraine (2022), which violates Article 2(4) of the UN Charter and has led to claims for reparations before the ICJ.
- Other recent cases include the Israeli occupation of Gaza, with allegations of war crimes and the blockade of humanitarian aid documented by the UN.[9]
Compliance mechanisms remain weak. Although ICJ judgments are binding, they lack automatic enforcement mechanisms. The ICC also faces challenges since some States (e.g., the USA, Russia, China) have not ratified the Rome Statute, and countries such as Hungary have openly defied arrest warrants against leaders like Benjamin Netanyahu.[10]
4. International Humanitarian Law and Human Rights
International Humanitarian Law (IHL) regulates the conduct of States and armed actors in conflicts. Its core consists of the 1949 Geneva Conventions and the 1977 Additional Protocols, which establish the protection of civilians, prisoners of war, and humanitarian personnel.[11]
- Violations of IHL, such as the attacks on hospitals in South Sudan (2025), are considered war crimes prosecutable by the ICC.
- The human rights system is structured around treaties such as the International Covenant on Civil and Political Rights (1966) and regional courts (European and Inter-American Courts of Human Rights).[12]
Despite these advances, the massive non-compliance observed in conflicts such as Gaza or Sudan highlights that the effective enforcement of IHL ultimately depends on political will and international pressure.[13]
5. International Institutions (UN, ICC/ICJ, etc.)
The United Nations (UN) remains the principal multilateral body. Its Security Council is tasked with maintaining peace, although the veto power of its permanent members often blocks key decisions.[14]
- The ICJ settles disputes between States and issues advisory opinions.
- The ICC, established under the Rome Statute (1998), prosecutes individuals for serious crimes, though its reach is limited by the lack of cooperation from certain States.
Institutions such as the WTO, WHO, or the IMF complement this legal framework, each with specific normative competencies in their respective areas.[15]
6. Peaceful Settlement and Dispute Mechanisms (ICJ, Arbitration, Diplomacy)
Article 2(3) of the UN Charter obliges States to settle disputes by peaceful means. These include negotiation, mediation, arbitration, regional arrangements, and the ICJ.[16]
- The South China Sea Arbitration (Philippines v. China, 2016) rejected the “nine-dash line” claim, but Beijing has ignored the ruling.[17]
- Conflicts such as Kashmir (India–Pakistan) and the dispute over the Preah Vihear Temple (Thailand–Cambodia) illustrate the fragility of regional diplomacy.[18]
- The war in Ukraine, described by Russia as a “special military operation,” underscores the failure of the Security Council to prevent conflicts.[19]
7. Contemporary Challenges: Climate Change, Cybercrime, Migration
PIL faces unprecedented challenges:
- Climate Change: In 2025, the ICJ issued an advisory opinion obliging States to protect the climate under the principle of preventing transboundary harm.[20]
- Cybercrime: Attacks on critical infrastructure (e.g., hospitals, power grids) raise the question of whether a large-scale cyberattack could qualify as a “use of force” under Article 2(4) of the Charter.[21]
- Migration: More than 120 million forcibly displaced people (2025) expose the shortcomings of the refugee regime and the principle of non-refoulement.[22]
8. Critical and Institutional Theoretical Perspectives
Diverse schools of thought enrich the interpretation of PIL:
- Realism regards international law as a reflection of power relations.[23]
- Liberal institutionalism emphasises the progress achieved by multilateral institutions.
- Critical and postcolonial theories (TWAIL) denounce structural inequalities within the system.[24]
- Feminist and ecological perspectives advocate for a more inclusive and sustainable framework.[25]
Conclusion: Public International Law at a Crossroads (2025)
As of July 2025, PIL is experiencing one of its most critical moments since the end of the Cold War. Recent breaches — such as Russia’s aggression in Ukraine under the euphemism of a “special military operation,” humanitarian law violations in Gaza, genocide in Darfur, or the open rejection of arbitral awards in the South China Sea — have cast doubt on its coercive capacity and universal legitimacy.[26]
Yet, this diagnosis should not be mistaken for a verdict of failure. The history of PIL shows that its evolution has been shaped by crises that lead to deep reforms. Just as the League of Nations arose after World War I, and the UN was born out of World War II, the current scenario may be the starting point of a new era of normative strengthening.
The Resilience of the Normative System
Despite breaches, PIL has demonstrated structural resilience
- ICJ rulings, such as South Africa v. Israel, or arbitral awards in the South China Sea, continue to hold moral and legal weight, reminding States of their obligations.
- The concept of ius cogens, which prohibits genocide, aggression, and torture, remains a legal red line that no State can derogate.[27]
Reforms and New Agendas
The international system requires structural reforms, many of which are already under discussion:
- Reform of the Security Council, to limit the veto in situations involving mass atrocities.
- Strengthening of the ICC, with binding enforcement mechanisms.
- Integration of new global challenges — such as climate change, cybercrime, and artificial intelligence — into universal international treaties.[28]
The Role of Civil Society and Regional Alliances
- The Role of Civil Society and Regional Alliances Beyond States: Civil society, NGOs, and transnational movements (such as Fridays for Future or campaigns against war crimes) have demonstrated an increasing influence on the international agenda.
- Regional alliances — ASEAN, EU, AU — have assumed more proactive roles in dispute resolution, mediation, and humanitarian response.[29]
A Hopeful Outlook
Although PIL is endangered by the weakening of international consensus, signs of renewal are visible:
- The ICJ’s 2025 advisory opinion on climate change has paved the way for a stronger environmental law framework.
- Advances in international criminal justice, though limited, show that impunity is not absolute (e.g., convictions of military leaders in Africa and Eastern Europe).
- Academic and political debates are increasingly focused on democratising and revitalising multilateral institutions.[30]
Ultimately, Public International Law is not at its endpoint but in transition. The international community faces the choice of strengthening norms and enforcement mechanisms, or resigning itself to a world ruled by power without law. Choosing the former is not merely a legal issue but an ethical imperative for humanity’s survival.
References
[1] Shaw, M. N. (2021). International Law (9th ed.). Cambridge University Press.
[2] Cassese, A. (2005). International Law (2nd ed.). Oxford University Press.
[3] Brownlie, I. (2008). Principles of Public International Law (7th ed.). Oxford University Press.
[4] Crawford, J. (2019). Brownlie’s Principles of Public International Law (9th ed.). Oxford University Press.
[5] United Nations. (1945). Charter of the United Nations. https://www.un.org
[6] International Court of Justice. (2024). South Africa v. Israel: Provisional Measures.
[7] Permanent Court of Arbitration. (2016). The South China Sea Arbitration (Philippines v. China).
[8] International Law Commission (ILC). (2001). Draft Articles on Responsibility of States for Internationally Wrongful Acts.
[9] The Guardian. (2025, January). International Law Under Siege: From Gaza to Ukraine.
[10] AP News. (2025, May). Hungary Defies ICC Arrest Warrant for Netanyahu.
[11] Geneva Conventions, 1949, and Additional Protocols, 1977.
[12] UN Human Rights Committee. (1966). International Covenant on Civil and Political Rights.
[13] ICRC. (2016). Commentary on the First Geneva Convention.
[14] Weiss, T. G., & Daws, S. (2018). The Oxford Handbook on the United Nations. Oxford University Press.
[15] Koh, H. H. (2019). The Trump Administration and International Law. Oxford University Press.
[16] United Nations. (1945). Charter of the United Nations.
[17] Permanent Court of Arbitration. (2016). South China Sea Arbitration Award.
[18] International Court of Justice. (2013). Temple of Preah Vihear (Cambodia v. Thailand), Interpretation Judgment.
[19] UN General Assembly. (2022–2024). Resolutions on Ukraine under the Uniting for Peace Procedure.
[20] International Court of Justice. (2025). Advisory Opinion on Climate Obligations of States.
[21] Shackelford, S. (2022). Cybersecurity Law and Policy. Edward Elgar Publishing.
[22] UNHCR. (2025). Global Trends: Forced Displacement 2025.
[23] Morgenthau, H. J. (1948). Politics Among Nations: The Struggle for Power and Peace. Alfred A. Knopf.
[24] Anghie, A. (2021). Imperialism, Sovereignty and the Making of International Law. Cambridge University Press.
[25] Charlesworth, H., & Chinkin, C. (2020). The Boundaries of International Law: A Feminist Analysis. Manchester University Press.
[26] The Guardian. (2025, January). International Law Under Siege: From Gaza to Ukraine.
[27] Orakhelashvili, A. (2008). Peremptory Norms in International Law. Oxford University Press.
[28] Weiss, T. G. (2023). Would the World Be Better Without the UN? Polity Press.
[29] Acharya, A. (2021). Constructing Global Order: Agency and Change in World Politics. Cambridge University Press.
[30] Slaughter, A.-M. (2022). A New World Order. Princeton University Press.