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Public International Law


Combining different disciplines, Leiden University researchers work together to formulate innovative solutions to societal problems. Below is an example from the field of law.

Overview research dossiers


Peace and justice in the 21st century

We would all like to live in a world in which individuals feel safe, conflicts are resolved peacefully and the interests of future generations are taken into consideration. At Leiden University legal scholars investigate to what extent public international law meets the needs of a globalised society. All scholars are members of the Grotius Centre for International Legal Studies of Leiden Law School, with offices in Leiden and on Campus The Hague.

<p>The Sudanese President Omar-al-Bashir is wanted by the International Criminal Court.</p>

The Sudanese President Omar-al-Bashir is wanted by the International Criminal Court.

Globalisation also touches the law

As recently as half a century ago, public international law primarily reflected the needs of a limited number of States: the maintenance of friendly international relations, the resolution of disputes and the protection of their sovereignty. This is no longer the case. Today public international law operates in an increasingly globalised society. Multinationals such as Royal Dutch Shell seek protection for their worldwide investments. War criminals from the former Yugoslavia and the Democratic Republic of Congo can be put on trial in The Hague, and international organisations are increasingly made responsible for resolving transnational problems and challenges, such as climate change, the pollution of the environment and economic development. The international society has evolved over the years and so has the law, but sometimes it lags behind.

Eliminating bottlenecks

The members  of the Grotius Centre seek to make sure that peace and justice are safeguarded in this new and complex world, focusing primarily on the bottlenecks that may arise in practice. For example, how can individuals be protected against the power of the UN Security Council now that the Security Council no longer imposes sanctions only on States, but also on individuals? Can an international organisation be held accountable before a national court? Should the law of armed conflict or international humanitarian law be modernised now that States make use of digital means and methods of warfare, such as unmanned and even autonomous weapon systems? To what extent does the law protect the environment and natural resources before, during, and after an armed conflict? Is secession allowed under public international law and what is the scope of the right of self-determination of peoples? And to what extent should questions of sustainable development, anti-corruption norms and the protection of human rights play a role in solving international trade and investment disputes?

Eyes wide open

The members of the Grotius Centre may each have their own area of expertise, but they certainly look at these issues in a wider perspective. After all, the various areas of public international law are closely related. Not only do they work together on certain projects, by also cooperate with scholars from other disciplines. By working together with historians, sociologists, economists and political scientists, they develop a better understanding of the (world behind) the law. For example, a team of researchers recently visited a number of African countries in order to look at the impact of the decisions of the International Criminal Court in The Hague. By doing so, they intend to improve the functioning of the Court.

Scholarship and legal practice

You can only suggest relevant solutions if you understand legal practice. This is why the members of the Grotius Centre combine legal scholarship with legal practice. They maintain close relationships with the International Court of Justice in The Hague, the Ministries of Foreign Affairs and Justice, the Security Council in New York, and various human rights bodies in Geneva. They are appointed as commissioners, appear as experts in arbitral proceedings, and teach judges, lawyers and administrators in various stages of their careers. The results of their research are therefore not only available in scholarly publications, but are also shared with those who are responsible for making the rules and finding justice.

Promoting international criminal justice

How should the international community of states respond to genocide, war crimes and crimes against humanity? How can the perpetrators of international crimes be brought to justice? How can international crimes be prevented? How can the international community of states promote international consensus while bridging gaps and cultural differences? The members of the Grotius Centre are working on such issues and thus promote the distribution of international criminal justice around the world.

The impact of the Criminal Court

In June 2012 the International Criminal Court rendered its first judgment in the case against Lubanga, a war criminal from the Democratic Republic of Congo. The Court convicted him of various war crimes, including the large-scale recruitment and use of child soldiers, and sentenced him to twelve years’ imprisonment. Twenty-two cases have since been brought before the Court relating to nine situations – all of them in Africa – resulting in two convictions. Members of the Grotius Centre, including Carsten Stahn, Larissa van den Herik, and Bill Schabas, deal with issues of international criminal law and investigate, among other things, the impact of the judgments and decisions of the International Criminal Court in the states where these crimes were committed. These are often states where the rule of law is still under development. Together with others, members of the Grotius Centre analyse media reports and conduct surveys and interviews with the victims and local law enforcers. They also seek to reconcile the differences between the wishes and customs of the Member States on the one hand and the responsibilities of the International Criminal Court on the other hand. More cooperation and closer collaboration between the Court and the local authorities would be a step in the right direction.


‘The International Criminal Court is still relatively young and intends to to give the inhabitants of traumatised countries such as Congo the feeling that justice is done in their name,’ says Larissa van den Herik about her research. ‘But that is by no means self-evident when the judgments are delivered in The Hague. In Africa, some people qualify the activities of the International Criminal Court as neo-colonialist. This raises the question of when international intervention is appropriate.

The International Criminal Court in The Hague (Photograph: Vincent van Zeijst, via Wikipedia Commons)

The International Criminal Court in The Hague (Photograph: Vincent van Zeijst, via Wikipedia Commons)

Is election violence a matter for the International Criminal Court? Does the Court focus too much on Africa? Can the Court also play a role in the Middle East, in Palestine or with respect to IS? These are questions that members of the Grotius Centre seek to answer. They analyse the law without losing sight of the relevant political context and the dynamics of the international community.

Punishment and reconciliation

The International Criminal Court is just one of the instruments for promoting international criminal justice. It is supplemented by ad hoc tribunals (such as the International Criminal Tribunal for the Former Yugoslavia, the International Criminal Tribunal for Rwanda, the Special Tribunal for Lebanon and the Special Court for Sierra Leone), commissions of inquiry (such as the commission investigating human rights violations in Darfur), and truth and reconciliation commissions (such as the truth and reconciliation commission in South Africa). In a globalised world it is logical that an increasing number of judicial, but also non-judicial organisations promote international criminal justice across the world. Members of the Grotius Centre seek to ensure that these organisations work with and learn from each other. They organise seminars to establish dialogue between the parties involved. Or they formulate guidelines and best practices. There is no need to constantly reinvent the wheel, and the victims are not forced to repeatedly recount their traumatic experiences before various institutions. A more theoretical question is whether non-judicial commissions interpret the law differently than judges, and if so, what the consequences are.

Sustainable international trade

The relationship between States and foreign corporations are regulated by international economic law and international investment law in particular. Any disputes between States and foreign corporations must therefore also be solved by reference to this body of public international law, for example when a State does not honour its agreements with a corporation. But a State may have good reasons for not observing its obligations towards such corporation, such as protection of the natural environment or respect for human rights. International investment law offers little room for these kinds of arguments. Nico Schrijver and Eric de Brabandere are top researchers of the Grotius Centre who focus on this jurisdiction. Both are also active in judicial practice.

Investment protection

Developing countries are keen to negotiate investment protection agreements with foreign investors. After all, these investors provide for infrastructure, employment and prosperity. They may invest in gold mines, oil extraction or logging, or they may take over privatised companies. States and investors lay down their agreements in concessions and contracts. Furthermore, international treaties, such as bilateral investment treaties, between industrial States (where the investors are based) and developing countries ensure that these agreements are observed and that the interests of the investors are protected.


Developing countries therefore have obligations both towards the foreign investors directly and towards the States where these investors are based. But developing countries also have obligations towards their own populations, whom they have to protect and to whom they are accountable. Sometimes, these countries let the interests of their own people prevail over those of the investors. For example, in the 1990s in Argentina, a French investor was forced to keep the price of drinking water artificially low. In South Africa, following the Apartheid, mining companies were forced to transfer some of their possessions to black South Africans.

In Germany, foreign investors are not happy with the decision of the German government to move away from nuclear energy. Australia has irked tobacco producers by making it compulsory for cigarette packs to be dark brown with deterrent notices and images instead of brand names. And an American oil company is embroiled in a lengthy international procedure with Ecuador following a conflict about the exploitation of oil fields, environmental pollution and damage to human health.

Protest against the presence of Shell in Canada. The group refers to 'Shell's exploitive and destructive history in Nigeria.'

Protest against the presence of Shell in Canada. The group refers to 'Shell's exploitive and destructive history in Nigeria.'

Reconciling two worlds

Eric de Brabandere has noticed that investors are increasingly filing claims against States. In a growing number of cases, these claims are submitted to international arbitral tribunals established by the company and the State involved. The awards of such tribunals are binding for both parties. In these kinds of conflicts, the private and commercial interests of both parties conflict with the public international legal character of the arbitration procedure. De Brabandere decided to find ways to reconcile the two. ‘It is legitimate for States to appeal to their sovereign duty to protect health and environment. This means that in such a conflict, public legal principles clearly play a role. It seems highly artificial to try and keep these principles out when resolving such conflicts, and rely only on the private aspects of investment law.’

Open the doors

De Brabandere performed a thorough analysis of the existing arbitration practices worldwide and their potential bottlenecks. This research resulted among other things in a monograph in which he offers arguments for the integration of investment law within public international law. When settling these kinds of disputes, it is essential to take public interests into account. Human rights and environmental organisations can under certain conditions be heard by arbitral tribunals, the decision making need not take place behind closed door, and arbitration tribunals can award other forms of reparation than financial compensation to corporations, such as restitution. ‘I hope and expect that my research will impact the way in which arbitrators look at disputes,’ says De Brabandere. ‘That when dealing with international trade conflicts, people will not only look at the commercial aspects of the dispute, but also at legal principles. Very slowly, you see that mentalities are shifting. I hope to have been able to contribute to this shift.’

International organisations and the rule of law

International organisations that represent collaborations between States are becoming increasingly more powerful, and they have an increasing impact on our daily lives. For example, the European Court of Human Rights in Strasburg established that minors have a right to legal aid immediately following an arrest and that a lawyer must be present at all times during police interrogations. The UN Security Council can impose a travel ban on anyone suspected of terrorism. Members of the Grotius Centre investigate how the law is applied by and within these organisations and how this can be improved.

Weapons and whales

Since the end of World War II, States have established international organisations with a large variety of responsibilities. International organisations have been established, for example, to enforce the prohibition on chemical weapons (OPCW), to promote world trade (WTO), to implement free trade and integration in Europe (EU), and to protect whales (IWC). There are currently more than six hundred of such organisations. In order to guarantee their independence, many of these organisations and their staff enjoy immunity from jurisdiction. But as their powers increase, they are also increasingly held accountable and even responsible. Should such responsibility be established before a domestic court and does this mean that the immunity of international organisations should be limited? Or are there other ways of realising accountability?

Wrongs committed during peace missions

The ‘Mothers of Srebrenica’ have for years been litigating with varying degrees of success against the UN and the State of The Netherlands because they are of the opinion that the UN and The Netherlands did not do enough to prevent the genocide that occurred after the fall of Srebrenica on 11 July 1995. Haitians have failed in their attempts to hold the UN responsible for a devastating cholera epidemic caused by Nepalese UN soldiers. How can international organisations maintain their

Mothers of Srebrenica in court in The Hague before their trial against the Dutch State. Dutchbat was responsible for defending the Bosnian Muslim enclave of Srebrenica. Srebrenica fell in July 1995 when the Bosnian-Serbian General Mladic crushed the enclave. Thousands of Bosnian Muslims were murdered. (Photograph: ANP / Koen van Weel)

Mothers of Srebrenica in court in The Hague before their trial against the Dutch State. Dutchbat was responsible for defending the Bosnian Muslim enclave of Srebrenica. Srebrenica fell in July 1995 when the Bosnian-Serbian General Mladic crushed the enclave. Thousands of Bosnian Muslims were murdered. (Photograph: ANP / Koen van Weel)

independence on the one hand, while on the other hand continue to guarantee that the victims of any wrongs committed during peacekeeping operations mistakes can have access to justice?

This is one of the central questions in the research of Niels Blokker and Nico Schrijver. They compared how different European States deal with immunities of international organisations and organised a conference to create a dialogue between various stakeholders. Case-law shows that the scope of the immunities of international organisations is interpreted differently in different parts of the world. Furthermore, the European Court for Human Rights has established certain criteria which international organisations must meet in order to retain their immunity. ‘Through this conference and a number of publications, we maintain dialogue,’ say Blokker and Schrijver. ‘In this way we hope to contribute to the improvement of the functioning of international organisations and legal certainty for private individuals.’

Black list

Sanctions against States often affect the most vulnerable parts of society, while the leaders remain firmly ensconced in their privileges. This is why the Security Council increasingly chooses to impose targeted sanctions on specific individuals. But what happens if you suddenly find yourself on a black list as a suspected terrorist? You are not allowed to travel, your assets may be seized and your reputation ruined. But what if you are innocent? How can you make sure that your name is removed from this black list? Larissa van den Herik researched  judicial protection in the case of sanctions imposed on individuals. ‘The Security Council is an intensely political organ. However, now that it focuses directly on individuals, rules are required to protect the individual against arbitrary decisions,’ says Van den Herik. ‘For example rules about the burden of proof are required to be able to categorise someone as a suspected terrorist.’ Thanks to the advice of Van den Herik and Schrijver, in collaboration with the Watson Institute, a step in the right direction has already been undertaken: the Security Council has appointed its own Ombudsman. If someone is of the opinion that they are the victim of unwarranted sanctions, they can appeal to this Ombudsman. But this procedure is only applicable in case of terrorism sanctions and not to other sanction regimes, so there is still a long way to go in further disciplining the Security Council.


Scientists working in this multidisciplinary research area

  • Prof. dr. Niels Blokker
  • Dr. Eric de Brabandere
  • Dr. Mr. Drs. Daniella Dam-de Jong
  • Dr. Simone van den Driest
  • Prof. dr. Helen Duffy
  • Prof. dr. Horst Fischer
  • Dr. Robert Heinsch
  • Prof. dr. Larissa van den Herik
  • Dr. Erik Koppe
  • Mr. Joseph Powderly
  • Dr. Yannick Radi
  • Dr. Cecily Rose
  • Prof. dr. Alfred van Staden
  • Prof. dr. Carsten Stahn
  • Prof. dr. William Schabas
  • Prof. dr. Nico Schrijver
  • Prof. dr. Kees Waaldijk

Prof. dr. Niels BlokkerProfessor of International Institutional Law

Topics: International institutional law, international organisations, United Nations, Security Council

+31 (0)71 527 8830

Dr. Eric de BrabandereAssociate Professor of Public International Law

Topics: International dispute settlement, international arbitration, international investment law, public international law

+31 (0)71 527 7399

Dr. Mr. Drs. Daniella Dam-de JongAssistant Professor of Public International Law

Topics: Natural resources governance, international humanitarian law, international environmental law, peace and security, sustainable development, UN Security Council and conflict resolution

+31 (0)71 527 7944

Dr. Simone van den DriestAssistant Professor of Public International Law

Topics: Public international law, right to self-determination of peoples, secession, human rights

+31 (0)71 527 5489

Prof. dr. Helen DuffyProfessor of International Human Rights and Humanitarian Law

Topics: Human rights law, trans-judicial and interplay of legal regimes, terrorism and international law, slavery and human trafficking, reparation and accountability

+31 (0)71 527 6444

Prof. dr. Horst FischerProfessor of International Humanitarian Law

Topics: International humanitarian law, international penal law, armed conflict, United Nations, European Union

+31 71 527 7578

Dr. Robert HeinschAssociate Professor of Public International Law

Topics: Public international law, sources of public international law, use of force, international humanitarian law, international criminal law

+31 (0)71 527 7581

Prof. dr. Larissa van den HerikProfessor of Public International Law

Topics: Peace and Security, United Nations and sanctions, commissions of inquiry, genocide and international criminal law, counterterrorism and international law

+31 (0)71 527 7533

Dr. Erik KoppeAssistant Professor of Public International Law

Topics: Public international law, peace and security, protection environment during international armed conflict, nuclear weapons, Dutch civil procedure

+31 (0)71 527 5218

Mr. Joseph PowderlyAssistant Professor of Public International Law

Topics: Crimes against humanity, theory international criminal law, theory international public law, tribunals

+31 70 800 9366

Dr. Yannick RadiAssistant Professor of Public International Law

Topics: International investment law, arbitration, international dispute settlement, global economic governance, history and theory of international law

+31 (0)71 527 7429

Dr. Cecily RoseAssistant Professor of Public International Law

Topics: international dispute settlement, human rights law, international criminal law, international economic law, international legal theory

+31 (0)71 527 5385

Prof. dr. Alfred van StadenProfessor of International Relations

Topics: International relations, international security, European integration, foreign politics

+31 (0)71 527 8937

Prof. dr. Carsten StahnProfessor of International Criminal Law and Global Justice

Topics: International criminal law, international courts and tribunals, peace and security, law of international organizations, transitional justice

+31 (0)70 800 9572

Prof. dr. William SchabasProfessor of Human Rights Law and International Criminal Law

Topics: International human rights law, international criminal law, death penalty, genocide

+31 70 800 9575

Prof. dr. Nico SchrijverProfessor of Public International Law

Topics: Public international law, United Nations, peace and security, sustainable development and management of natural resources, human rights, right of the sea, international dispute settlement

+31 (0)71 527 8936

Prof. dr. Kees WaaldijkProfessor of Comparative Sexual Orientation Law

Topics: Sexual orientation law, gay/lesbian partnership, discrimination, comparative law

+31 (0)70 800 9593


Students learn directly from researchers

In the field of public international law, Leiden Law School not only has a long tradition, but also a unique position thanks to the proximity of The Hague, City of Peace and Justice. In The Hague students can see international justice in practice, take an internship at one of the many international organisations, or choose from a wide range of symposiums and lectures blending scholarship and practice.

Members of the Grotius Centre for International Legal Studies teach courses in the various Bachelor’s programmes of Leiden Law School. At the Master’s level, they are responsible for the regular programme in Public International Law and a small-scale Advanced Master’s programme in Public International Law. Both Master’s programmes draw students from all over the world.

Beyond the Law School, members of the Grotius Centre also teach at the Faculty of Social and Behavioural Studies in Leiden and at Campus The Hague. In addition, they offer a number of specialised summer courses, a Massive Open Online Course (MOOC) on Courts and Tribunals, video lectures about specific topics for the UN Audiovisual Library of International Law and give guest lectures all over the world.

A class led by Prof. dr. Niels Blokker A class led by Prof. dr. Niels Blokker

Outreach & News

Science at the heart of society

Our research reaches further than the academic world alone. Our experts are often invited to international conferences and discussion meetings that are open to the wider public. In addition they often offer comments in the media and share their knowledge online.



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