Commentary on Remembering Peace in a Time of War:
Why International Law Matters More Than Ever
By Patricia Galvão Teles
Published on 18 July 2025
At the time the world’s attention is so focused on war and conflict, it is important to remember and think about peace.
The history of humankind has been filled with war and conflict. Unfortunately, that is nothing new. What is new in the last 80 years, since the creation of the United Nations (UN) in 1945, is that the world is committed to a peace project. And it is why, 80 years after the UN’s formation and despite present circumstances, it is fundamental not to forget that.
Today, international law is based on fundamental principles that are instrumental for peace: sovereign equality, non-interference in domestic affairs, prohibition of the use of force, self-determination, and human rights.
International law can play a key role in promoting peace. In preventing war and conflict through the rules contained in the UN Charter on the prohibition of the use of force and the role of the Security Council, to arms controls treaties that help control the spread and used of weapons, and the Geneva Conventions and other international humanitarian law treaties that alleviate suffering during conflict. By providing for instruments of peaceful settlement of disputes as the International Court of Justice and arbitration and mediation mechanisms. Through universal and regional mechanisms for protection and promotion of human rights and to deal with the prosecution of the most serious international crimes by providing the legal tool for establishing global norms and institutions to deal with the most pressing issues facing the international community.
There are, of course, important challenges that affect the role that international law can play in promoting peace: geopolitical interests, double standards and selective enforcement, new actors such as terrorist groups, new technologies such as autonomous weapons, operations in the cyberspace and artificial intelligence, or new global challenges that require action by the whole of the international community such as climate change.
But we need to talk about peace—and not just about conflict—more.
If we look back to the Cold War, it was a difficult period that cast doubt and shadow on the prospects of peace just as the United Nations was created. It blocked the work of one of its fundamental organs, the Security Council. In addition, the UN’s principal judicial organ, the International Court of Justice, had a slim docket in the first decades of operation.
Nevertheless, the development of international law during the Cold War was intense and even flourished, with a significant increment in the number of multilateral, regional and bilateral treaties that created a bases for cooperation in all areas of activity: transport, trade, environment, telecommunications, oceans and law of the sea, criminal matters, and so on.
It is a lesson that we cannot forget. Even during the Cold War, it was possible to make international law stronger and the basis for peace. It was during the Cold War that decolonisation happened, and that many of the fundamental treaties we have today were negotiated and adopted, including (among many others) the United Nations Convention on the Law of the Sea, and the Vienna Conventions on Diplomatic and Consular Relations and on the Law of Treaties.
It was also in the aftermath of the Cold War that peace and conflict resolution became permanent objectives; based on international law by preventing the violation of fundamental principles from becoming lawful through the mere passage of time. Through international law’s fierce resistance, it was possible to end apartheid in South Africa, and for Timor-Leste to finally exercise its right to self-determination and become independent.
Today, even in the turbulent—and hard to classify in terms of war and peace—world that we are living in, States are not contesting the relevance of international law and its role for peace. In some instances, it seems quite to the contrary. For example, and in contrast with the Cold War period, the International Court of Justice has never been busier.
It is thus imperative to continue to resist and to pursue and promote peace through international law.
The present CIL Dialogues´ Symposium on Peace and International Law could not therefore be timelier. It explores how peace can be manufactured, built, and brokered, and the role that international law can play in its regard. It explores peace in its different dimensions such as dealing with conflict, peaceful settlement of disputes, development, human rights, and new technologies, just to mention some examples.
As we celebrate Mandela Day today on 18 July, it seems appropriate to close this brief commentary with a quote from one of the world’s leaders that has made in the last 80 years one the greatest contribution to peace and international law through his life, actions and leadership, which won him the Nobel Peace Prize:
“Peace is the greatest weapon for development that any person can have. It is what the people of the world need and deserve.”
— Nelson Mandela, Message for the 8th Nelson Mandela Annual Lecture, 2010