The emergence of new armed conflicts in the 21st century seems to call into question the foundations of international law and the effectiveness of the international legal order. Even though the general ban on the use of force in the UN Charter does not seem to prevent new armed conflicts from breaking out, international law still plays an important role today. International politics is cyclical. The international legal order might return to being more effective in the future.

Russia’s aggression against Ukraine, the terror attack on the 7th of October 2023 and the following Gaza war, the American intervention in Venezuela and the armed conflicts between Iran, Israel and the United States among other examples show that, unfortunately, war has not disappeared in the 21st century. Many pose the question whether international law continues to play a role in global politics, whether it is still in force and effective (with more than 120 ongoing armed conflicts) or whether a new international order is emerging based on sheer power-politics.  

There is no question that the general ban on the use of force (Art 2 (4) of the UN Charter) is in force today, stating that „All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations”. The General Assembly of the UN adopted resolution A/RES/ES-11/1 on 2 March 2022 stating in its Art 2: „Deplores in the strongest terms the aggression by the Russian Federation against Ukraine in violation of Article 2 (4) of the Charter”. This indicates that the jus contra bellum is in fact, in force, however, it is unable to prevent states from attacking one another, especially if they are one of the great powers of the world.

The interest of mankind is in avoiding any wars, which is also an ethical obligation and international law aligns with ethical principles on questions of war and peace. However, the brutal reality of war has not disappeared after so many horrible experiences of humankind.

It seems like the current structure of the international legal order, having permanent members with veto rights in the UNSC, leads to a situation, where the great powers and the allies they support avoid, the obligation stemming from the UN Charter, while the smaller states with less influence still have to abide by it. Nevertheless, there are important consequences of the general ban of the use of force being in force today.

Every state, even the greater ones, must contemplate the (domestic and international) political costs of applying force to another state. Politicians are trying to avoid using the term „war” (used by the 1907 Hague Conventions as well), while the terms international and non-international armed conflict introduced by the 1949 Geneva Conventions are unknown to the public. The argument that it is better to regulate something than let it fall into chaos applies to the general ban on the use of force as well. Furthermore, international law does have sanctions, as all legal branches ought to, only in this case the sanctions exist on a systematic level. One does not know what the future entails; individuals committing the crime of aggression may end up before an international or domestic criminal court in the future.

In a way, something analogous to the theory of just war seems to be emerging. The roots of this concept can be traced back to the Middle Ages (to Christian thinkers, St. Augustine and Thomas Aquinas among them), where on one side, parties were fighting a just war in line with divine law, while on the other side fought the unjust parties, who may not be supported by other sovereigns, only the just party. The general ban on the use of force is similar in a way that there is an aggressor state and there is a victim state in international armed conflicts. The problem, however, of how to force the aggressor not to wage unjust war remains in the 21st century. Still, the theory of just war was one of the first early examples in legal history of restricting the right of the sovereign to wage war and thus it did have an effect of deterrence, just like jus contra bellum does today.

Thus, the situation is completely different with jus contra bellum being in force compared to a situation where it would not be in effect. The same applies to international humanitarian law (with a symbolic name aiming at decreasing human suffering) and its breaches as well.

The International Review of the Red Cross published in 2024 the 6th ICRC report on International humanitarian law and the challenges of contemporary armed conflicts. The report states that violations of fundamental rules remain of grave concern and even if parties contend that their actions were compliant with legal obligations, there are many challenges to international humanitarian law.

International humanitarian law deals with a range of issues, from the rules on the conduct of hostilities to the treatment of civilians, PoWs, aiding civilians, protecting environmental zones, etc. An important function of International Humanitarian Law is to enable humanitarian organizations to give aid to people in need in conflict-affected zones.

As is the case with jus ad bellum, the same applies to jus in bello as well: without international humanitarian law, people would not even have the highest moral obligation regulated by law to treat people with dignity and humanity in the worst situations possible. Due to this field of law being in force, many people are in a better situation than they would be without it. Those who breach the gravest norms of international law may face the consequences for the rest of their lives. In many cases during today’s armed conflicts, justice is being served.

International politics, like national politics, is cyclical. The international legal order might return to be more effective and even improve through successful, human-centered reforms in the future.

Árpád Lapu is an assistant research fellow at the Károli Gáspár University of the Reformed Church in Hungary. He was a policy adviser on constitutional issues at the European Parliament between 2019-2024. He worked as an adviser at the Ministry of Justice of Hungary (2017-2019) and the Ministry of European Union Affairs (2024-2026), conducting EU law, international law and comparative constitutional analyses. He has earned his JD at the Pázmány Péter Catholic University in Hungary, has a BA in international relations from the University of Szeged, and an MA in European and international administration from Andrássy Gyula German Speaking University in Budapest. He has completed an LLM in international law at the Catholic University of Louvain (UCLouvain).