Examining the Russian Attack Against Ukraine Through the Lens of International Law

© Photo by Міністерство внутрішніх справ України via Flickr

24 February 2022, a date that will long be remembered by the world as a flagrant violation of peace and international law.

At approximately 6 am local time in Moscow (03:00 GMT), Russian President Vladimir Putin announced his decision to conduct a military operation in Donbas (East Ukraine) and called upon Ukraine’s military to lay down arms. Putin justified the attack by citing the necessity of a “demilitarization and denazification of Ukraine”, and the need to protect people living in Donbas who, he claimed, had been subjected to “genocide.”  Furthermore, he stated that Russians actions were to be considered as acts of “self-defense against threats” and that there were no plans to occupy Ukraine. Putin also used this opportunity to warn both the United States (US) and NATO not to interfere or that they would face “consequences you have never seen.” Immediately after his speech, Russian missiles began hitting targets in Ukraine marking the start of an offensive by air, land and sea.  

Russia’s actions violate several instruments of international law, including the United Nations Charter and the Rome Statute (RS) of the International Criminal Court (ICC). Article 2(4) of the UN Charter prohibits the threat or use of force, whereas Article 8bis of the RS defines aggression as ‘the planning, preparation, initiation or execution, by a person […] who exercises control over or to direct the political or military action of a State, of an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the UN Charter.’ With these definitions in mind, this article seeks to illustrate the numerous violations of the principles regarding the prohibition on the use of force and the right to self-defense enshrined in the UN Charter. Furthermore, it will determine the importance of the crime of aggression in the Russian-Ukrainian conflict and the challenges posed by the commission of this crime, for international law.


The conflict in Ukraine commenced with demonstrations in Kyiv in 2013, the protests were against Ukrainian President Viktor Yanukovych’s decision to reject a deal for greater economic integration with the European Union (EU). As a consequence, President Yanukovych was forced to flee  the country in 2014. The same year, Russia, taking advantage of Ukraine’s instability, annexed Ukraine’s Crimean peninsula after Crimeans decided to join Russia in a controversial referendum. In May of 2014, pro-Russian separatists in the Ukrainian regions of Donetsk and Luhansk held a referendum to try achieve independence. In light of existing tensions, conflict erupted between separatist forces and the Ukrainian military, although Moscow denied supporting separatists.

In 2018, Ukraine, the US and other NATO countries started a series of large-scale military exercises in Ukraine in response to the military movements conducted by Russia in the same year.  In October 2021, Russia mobilized its army near the border with Ukraine  and by December, more than 100 000 Russian soldiers were stationed near the Russia-Ukraine frontier. Russia’s Foreign Ministry issued several demands calling for NATO to terminate military activity in Eastern Europe and to prevent Ukraine from joining the organization in the future.  In February 2022, in response to the military buildup near Ukraine, US President Joe Biden deployed around 3,000 US troops to Poland and Romania to counter Russian troops. Unfortunately, the subsequent negotiations between the US, Russia, France and Germany were unsuccessful. Instead Vladimir Putin ordered Russian troops to enter into Luhansk and Donetsk (i.e., the separatist regions in Eastern Ukraine) claiming that the troops served as peacekeepers. Matters escalated on 24 February, when Putin announced the beginning of a full-scale invasion of Ukraine during a United Nations Security Council (UNSC) meeting. As of 28 February 2022, Russian forces were advancing towards Ukraine’s capital, Kyiv, as they continued their assault.

Between the beginning of the conflict and 4 March 2022, over a million of civilians have fled Ukraine, seeking safety in neighbouring countries. Estimates by the UN and refugee organizations put the number of people fleeing the Russian invasion at 4 to 7 million. As of 8 March more than 2 million refugees have fled Ukraine  as the Russian assault continues. The US, the United Nations, G7, the EU, amongst others have condemned the Russian offensive and have since imposed restrictions targeting banks, military exports, and oil refineries.

On 2 March, the UN General Assembly (UNGA) adopted a resolution rejecting the Russian invasion of Ukraine and demanding that Russia withdraw its forces and abide by international law. Additionally, on March 4th, the UN Human Rights Council decided to setup an independent investigative commission on alleged human rights violations committed by Russia in Ukraine.

The Prohibition on the Use of Force and the Right to Self-Defense

The prohibition on the threat or use of force is a fundamental pillar within the international legal order.  Due to its status, it is also accepted as a norm of customary international law, as affirmed by the ICJ in Nicaragua v. USA , as well as, being considered a jus cogens rule (i.e. a peremptory norm from which derogation is not permitted). This principle is defined in Article 2 (4) of the UN Charter as follows, “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 exceptions to this rule (Articles 39, 42 and 51 of the UN Charter) were made for cases pertaining to the use of force in the form of individual or collective self-defense based on Article 51, and for the use of force to combat threats to international peace and security when authorised by the UNSC.

According to several States, the right of self-defense can have a preventive nature, for example, allowing the use of force when an armed attack against a State is imminent. In this sense, the resolution passed by the UNSC, after 11 September 2001, recognized that a large-scale terrorist act could constitute an armed attack that would give rise to the right of self-defense. Thus, the use of force might, under specific circumstances be used in self-defense against those who plan and perpetrate such acts. Therefore, as outlined by Daniel Bethlehem, “it must be right that States are able to act in self-defense in circumstances where there is evidence of further imminent attacks by terrorist groups, even if there is no specific evidence of where such an attack will take place or of the precise nature of the attack.”

In addition to the aforementioned right to self-defense, there are other justifications that can be used by States to validate the use of force. For example, the Genocide Convention imposes the obligation on States Parties to prevent genocide, which the ICJ recognized to have extra-territorial application. In addition, the Responsibility to Protect (R2P) implies that States must seek to ensure that the international community never again fails to halt the crimes of genocide, war crimes and crimes against humanity. According to the  World Summit Outcome Document, the use of force may be exercised when peaceful means fail to reach a result and,

 …to help protect populations from genocide, war crimes, ethnic cleansing and crimes against humanity. In this context, we are prepared to take collective action, in a timely and decisive manner, through the Security Council, in accordance with the Charter, including Chapter VII, on a case-by-case basis and in cooperation with relevant regional organizations as appropriate, should peaceful means be inadequate and national authorities manifestly fail to protect their populations from genocide, war crimes, ethnic cleansing and crimes against humanity.

With these frameworks in mind, Russia has attempted to proffer justifications for its ongoing attack. According to Putin, the aim of the attack is  

…to protect people who have been subjected to abuse and genocide by the regime in Kyiv for eight years. And for this we will pursue the demilitarization and denazification of Ukraine, as well as bringing to justice those who committed numerous bloody crimes against civilians, including citizens of the Russian Federation.

Based on these justifications, Russia seeks to argue that its actions do not violate the UN Charter or the Budapest Memorandum (in which Russia agreed to respect the sovereignty of Ukraine). While Putin tries to justify his actions based on the right to pre-emptive self-defense and the responsibility to prevent genocide in Donbas, there is a lack of reliable evidence of genocide, moreover, there are no threats from Ukraine to Crimea or to Russian territorial sovereignty (only then would such threats satisfy a right to preventive self-defense as stated above). Consequently, on 26 February 2022, Ukraine filed an application instituting proceedings against the Russian Federation before the International Court of Justice (ICJ), based on “a dispute . . . relating to the interpretation, application and fulfilment of the 1948 Convention on the Prevention and Punishment of the Crime of Genocide.” In its application, Ukraine mentioned that,

…the Russian Federation has falsely claimed that acts of genocide have occurred in the Luhansk and Donetsk oblasts of Ukraine, and on that basis recognized the so-called ‘Donetsk People’s Republic’ and ‘Luhansk People’s Republic’, and then declared and implemented a ‘special military operation’ against Ukraine.

Therefore, it becomes evident that the Russian “special military operation” in Ukraine is in fact an illegitimate use of force with no legal justification. Furthermore, it is an act of aggression which violates international law.

The Crime of Aggression

Aggression is considered to be one of the most controversial crimes in international criminal law. This crime involves the criminalisation of certain conducts of recourse to force or jus ad bellum. In the words of Carsten Stahn, “it thereby strengthens the trend towards a jus contra bellum in the international legal order, namely the restriction of the use of armed force in international relations. The nature of the crime differs partly from other crimes in that aggression is more diffuse and collective.”

The crime of aggression can be conceived of in three different ways, (1) as a crime against State sovereignty, (2) as a crime against peace and security and (3) as a crime against certain collective rights (i.e., right to self-determination) and individual rights. (Stahn, C. (2018). A Critical Introduction to International Criminal Law. Cambridge: Cambridge University Press. doi:10.1017/9781108399906)

The Charter of the International Military Tribunal at Nuremberg (IMT) marked, for the first time, the recognition of individual criminal responsibility for the commission of an act of aggression (also referred to as ‘crimes against peace’) which is found in Article 6(a) of the Nuremberg Charter as, “namely, planning, preparation, initiation or waging of a war of aggression, or war in violation of international treaties, agreements or assurances, or preparation in a common plan or conspiracy for the accomplishment of any of the foregoing.” In 1948, the IMT defined aggression as “not only an international crime; it is the supreme international crime differing only from other war crimes in that it contains within itself the accumulated evil of the whole.”

In 1974, following the same criteria as the IMT, the UNGA adopted Resolution 3314  which defines aggression as “the use of armed force by a State against the sovereignty, territorial integrity or political independence of another State, or in any other manner inconsistent with the Charter of the United Nations, as set out in this Definition.” The seven acts that constitute aggression are further developed in Article 3 of the Resolution and are included in the Rome Statute as discussed below.

Given its significance, aggression was one of the four core crimes included in the RS when it was adopted in 1998. However, the issues of establishing a concrete definition and the scope of the ICC’s jurisdiction over this crime were deferred for later determination. In 2010, after several days of negotiation, ICC States Parties established a definition, as well as, conditions for the application and jurisdiction for the crime of aggression which resulted in the adoption of the so-called Kampala Amendments. On 7 July 2018, after 30 ratifications, the resolution was finally adopted, activating the ICC’s jurisdiction over Member States which have ratified the RS and the amendments on the crime of aggression.

The final definition for the crime of aggression included in Article 8 bis of the Rome Statute reads as follows,

“Crime of aggression means the planning, preparation, initiation or execution, by a person in a position effectively to exercise control over or to direct the political or military action of a State, of an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations.”

In accordance with Resolution 3314 of the UNGA and the aforementioned article of the RS, the following acts are considered to be an act of aggression, regardless of a declaration of war. Namely, any invasion or attack by the armed forces of a State on the territory of another State, or any military occupation, or annexation; the use of any weapons by a State against the territory of another State; the blockade of the ports or coasts of a State by the armed forces of another State; an attack by the armed forces of a State on the military of another State; the use of armed forces of one State which are within the territory of another State with the agreement of the receiving State, in contravention of the conditions provided for in the agreement or any extension of their presence in such territory beyond the termination of the agreement; the action of a State in allowing its territory, which it has placed at the disposal of another State, to be used by that other State for perpetrating an act of aggression against a third State; the sending by or on behalf of a State of armed bands which carry out acts of armed force against another State that amount to the acts listed above.

Based on the provisions listed in the RS, the acts carried out by the Russian Federation fulfill the elements required to classify the attack as an act of aggression. However, given that neither Ukraine nor the Russian Federation are State Parties to the RS, the ICC cannot exercise jurisdiction over the crime of aggression. However, Ukraine has previously made declarations under Article 12 (3) of the RS, giving the ICC jurisdiction over genocide, crimes against humanity or war crimes committed in Ukraine since 20 February 2014 onwards. On 11 December 2020, the OTP announced the completion of the preliminary examination of the situation in Ukraine, concluding that there was a reasonable basis to believe that war crimes and crimes against humanity were committed in the context of the protests in 2013 and the armed conflict in the Donbas. Still, as Ukraine has not ratified neither the RS nor the Kampala Amendments, the ICC cannot exercise jurisdiction over the crime of aggression in this case. However, the alleged war crimes that are already occurring can be brought before the Court. Regarding this situation, ICC Prosecutor Karim A.A. Khan, stated that his Office will “proceed with opening an investigation into the Situation in Ukraine, as rapidly as possible.” On 2 March, Mr Khan confirmed that, the OTP had received referrals from 39 ICC States Parties of the Situation in Ukraine. The referrals enable the Prosecutor to proceed with opening an investigation on past and present allegations of war crimes, crimes against humanity and/or genocide committed on any part of the territory of Ukraine by any person. Following the previous statement of the ICC Prosecutor, the Presidency of the ICC has assigned the Situation in Ukraine to Pre-Trial Chamber II, composed of Judge Antoine Kesia-Mbe Mindua, Judge Tomoko Akane and Judge Rosario Salvatore Aitala. The judges will decide whether or not to authorise the Prosecutor to open an investigation into the Situation. They will also have to consider whether there is a reasonable basis to proceed with an investigation upon examination of the Prosecutor’s request and the supporting material.


Having examined the existing frameworks within international law, it becomes clear that the Russian assault against Ukraine is not only a manifest violation of the prohibition on the use of force, a cornerstone of the international legal order set up in the aftermath of World War II, but also a flagrant crime against peace that facilitates the commission of other international crimes, such as the perpetration of war crimes. Behind the rhetorical coverup of self-defense and protecting the people in Donbas from “genocide” are political ambitions to extort concessions by Ukraine to stay outside of NATO and the EU, revealing the truth of Putin’s invasion as a “continuation of politics by other means” as stated by Carl von Clausewitz. Putin and thus, Russia, are violating international law without facing immediate legal consequences, however this does not mean that international law is irrelevant or redundant. All the States and organisations that have condemned Russia’s invasion have also issued economic sanctions against Russia, in the order to not only defend Ukraine, but also seek to protect the principle of the prohibition on the use of force and other pillars of international law. Currently, the future of the conflict and its legal consequences remain uncertain, representing a turning point in contemporary international law.

Victor Calero is a final year law student at the Universidad de las Americas in Quito, Ecuador. He serves as a Blog writer at Platform for Peace and Humanity. He interned at Ortega y Grijalva Ecuadorian law firm, Lawyers in Palestine Program and Clooney Foundation for Justice. He is an intern at the Organization of American States where he works at the Inter-American Drug Abuse Control Commission. He has previously volunteered at Caritas Ecuador to provide legal assistance to indigenous communities and refugees. His areas of interest include International Criminal Law, Humanitarian Law and Human Rights.

Leave a Reply