International Law Commission advances rules-based world order

The international system would not function without international law. The International Law Commission is one of the UN's oldest special bodies, where a large part of the legal regulation for international relations has been prepared. The Commission's work has been of great importance in promoting the rule of law and justice internationally.

Marja Lehto
Ambassador and adjunct professor of international law Marja Lehto at the Ministry for Foreign Affairs' Merikasarmi building. As a member and special rapporteur of the International Law Commission, Lehto has tried to promote the transparency of the Commission's working methods. Photo: Laura Rantanen

The International Law Commission (ILC) of the United Nations (UN) has just concluded the last session of its current five-year term. In the past five years, the ILC has discussed peremptory norms and general principles of international law, legal implications of sea level rise, and the immunity of state officials from foreign criminal jurisdiction, among other matters.

Ambassador Marja Lehto, Adjunct Professor of International Law at the University of Helsinki, has been a member of the ILC since 2017. During her term as Special Rapporteur, Lehto has advanced the Commission’s work on the definition of the principles for environmental protection in relation to armed conflicts.

Marja Lehto, what is the ILC and what does it actually do?

The ILC is a UN body of experts tasked with promoting the progressive development and codification of international law in close cooperation with the UN General Assembly’s main committee for legal questions, the Sixth Committee. In practice, this means that the Commission prepares legal texts and reports every year on its work to the General Assembly.

What kind of an impact does the ILC have on states and their mutual relations?

The ILC is one of the oldest special bodies of the UN. It has prepared a key part of the legal regulation for international relations. The rules on diplomatic relations, consular relations, and the law of treaties, among others, are based on the ILC’s work. Its contribution has been significant in many fields, such as international criminal law, international maritime law, and the law of state responsibility.

Over the past decades, international regulation has expanded in scope and it has become more complex and split into special branches of law. The ILC’s role, increasingly, is to clarify and strengthen the general rules. In addition, the ILC has examined topical legal problems comprehensively from the perspectives of different fields of law.

A testament of the importance of what the ILC is doing is that many of its final texts have served as a basis for treaty negotiations and that both states and international courts are frequently referencing them.

Has the ILC changed the world in some way? How?

The ILC’s bread and butter is general international law, which means the principles and rules that apply equally to all states. Expanding the scope of generally binding rules facilitates the realisation of the rule of law at international level. For example, the International Criminal Court, whose statute was first drafted by the ILC, has held to account those responsible for the most serious international crimes.

Another area where the ILC has a vital role is the codification of the peremptory norms of general international law (jus cogens). States may never deviate from peremptory norms, not even by treaties, and other states may never recognise a situation (such as territorial claims following an armed aggression) resulting from a violation of these rules. 

Sea level rise as a result of climate change is a topic with a strong emphasis on fairness, considering that the small island states bearing the brunt of the effects are the least to blame for climate change.

Only four of the 34 members of the ILC were women during the current term. Are you worried about the unequal gender representation? How would you develop the ILC?

The unbalanced gender ratio in the ILC is a great cause for concern. Given the UN’s strong gender equality policies, the composition of the Commission is strange to say the least.

However, there is very little the Commission itself can do to redress the matter. All members are elected for the five-year term by the UN General Assembly, which means that the matter is decided both by the states that nominate candidates and by all the states when the time comes to vote in the election.

The current four female members of the Commission organised a side event in New York during the 70th anniversary of the ILC. The side event was called ‘7/70’ after the seven women elected as members of the Commission during its 70-year history. The event raised a lot of positive interest, and last autumn the election of the members of the ILC had a record high number of women as candidates. The number of women in the ILC only rose by one, though, showing that progress is slow.

What is positive is that one of the new female members is from Africa and another one from Asia. During the current term, all four female members are from Western countries.

Something that the Commission can influence is a more open approach. In my role as Special Rapporteur, I have been in touch with expert agencies, civil society organisations and the research community alike. When the ILC adopted the draft principles and commentaries on the protection of the environment in relation to armed conflicts on first reading in 2019, we asked and received written comments not only from states but also from international organisations and other stakeholders.

Recently the Association of Finnish Lawyers set up a discussion panel titled “Is international law just cannon fodder for dictators?” What kind of a role does international law have in today’s world?

The international system would not work without international law. State sovereignty is a legal construction, and the rights and obligations of states are laid down in international law. States need international rules for defining the limits of their competence in relation to other states, for safeguarding their interests and for collaborating in countless different ways. Many of the rules are like oil in the machine: they reduce friction and create legal certainty and a foundation for cooperation.

The rules of state responsibility and the various mechanisms for enforcing that responsibility, such as international courts and tribunals, uphold the international legal order.

Violation of the rules on use of force, of which Russia’s invasion of Ukraine is a flagrant example, gets a lot of attention for a good reason. The prohibition of the use of force is an exceptionally strong norm, and it is not weaker for being now breached. Often states justify their actions by invoking some of the exceptions to the ban, usually self-defence, which Russia, too, did in February.

Obviously, there were no grounds for the Russian Federation’s claim of having been the victim of an armed attack. The responsibility for the invasion and for the war crimes committed by its forces weighs heavy on Russia, and many legal proceedings against Russia are already under way.

You are the third Finn as member of the ILC. What are Finland’s goals in the ILC, and why is it important for us to have representation in the Commission?

My Finnish predecessors in the Commission were Professor Erik Castrén in the 1960s and 1970s and Professor Martti Koskenniemi from 2001 to 2006. None of the members represents his or her country or takes instructions from any individual state. However, being a member in the ILC and serving as Special Rapporteur brings positive publicity for the home country, too, or in my case to the Nordic countries. Both my predecessor Professor Koskenniemi and I were elected as Nordic candidates.

It is important that the impact of the Nordic legal culture is visible and that it leaves its mark on the Commission’s work.

Furthermore, the matters I have been working on are close to Finland’s foreign policy priorities: overall environmental goals, water diplomacy, protection of the environment in crisis management operations, humanitarian assistance and post-conflict peacebuilding, and strengthening corporate environmental responsibility.

As Special Rapporteur, you focused on environmental protection in and in relation to armed conflicts. Why is it an important topic and what has the ILC achieved? How can the international community, or Finland, benefit from the results?

There is very little international regulation on the environmental aspects of armed conflicts. For the most part, the conventions on international humanitarian law were drafted long before the emergence of international environmental law or environmental awareness. 

It is a notable achievement that with its 27 draft principles and commentaries the ILC has succeeded in clarifying, interpreting and developing applicable international law on environmental protection in and in relation to armed conflicts.

In general, the understanding of the environmental effects of armed conflicts has deepened in recent decades. One significant finding is that the environmental effects of armed conflicts are not limited to the direct damage caused by the use of weapons and that indirect damage and long-term damage can be much worse. It means that conflicts leave a long shadow on the environment, too.

The ILC’s work on the topic has made use of these findings. A broader perspective not only means a wider temporal scope but also attention to the obligations of states and actors that are not parties to conflicts. At the same time, it has been necessary to take into account not only international humanitarian law but also human rights and environmental aspects.

What are the benefits of all this? It is no longer possible to invoke the non-existence of rules on environmental protection in armed conflicts or an unclear legal situation. We have heard such arguments for instance in connection with situations of occupation. The ILC has defined a set of environmental obligations of the occupying power in relation to the occupied state, the population under occupation and to other states. 


International law evolves and develops at the interface of practical politics. It perseveres in demanding and seeking just answers and responsibility and solutions to the most pressing problems of our time. This is what the ILC is doing: it is creating and facilitating a more profound understanding of what international law does and can do. Nordic expertise has an important role in this work.

Rakel Jylhä-Vuorio

The author is a university intern at the Unit for Public International Law of the Ministry for Foreign Affairs.