Academic Research International Law

Russia’s Invasion of Ukraine: An Unjustifiable Breach of International Law

Dr Andrew Jones examines the extent to which Russia’s military invasion of Ukraine amounts to a violation of international law.

In the early hours of February 24th 2022, Russia began its anticipated invasion of neighbouring Ukraine. In defence of its actions, the Russian government has made various statements to justify its invasion in terms that are familiar to those versed in the law on inter-State use of force. However, the question needs to be asked, do these explanations justify the military incursion, or is Russia’s invasion a violation of international law.

This is undoubtedly an important question, and not one to be glossed over despite the generally united message of condemnation communicated by the international community. Rather, analysing and explaining the illegality of blatant acts of aggression such as this is vital for the continued validity and standing of the rules of international law.

Prohibition of Force and Self-Defence

According to the UN Charter, any use of armed force between nations is illegal, subject only to the exceptions of genuine acts of self-defence or UN Security Council authorisation. Certainly, the UN Security Council and its Permanent Membership have not authorised this action, nor would they if given the opportunity. Therefore self-defence would be the only entirely established and accepted justification upon which the Russian President, Vladimir Putin, could plant his flag. In a fiery speech given on Monday 21st February, Putin claimed, among many other things, that Ukraine was a puppet State for the US and that its potential membership to NATO was a direct threat to the Russian nation. This raises a now familiar debate on whether a State can take military action to defend itself from emerging threats.

Generally, the Charter’s law on self-defence requires there have been an armed attack. Setting aside the myriad of definitional complications surrounding that concept, an armed attack can generally be considered a serious incident involving the application of significant armed force by one State against another. The wording of this aspect of the law that any defence is permitted when an attack ‘occurs’ also suggests that it is backwards looking, with the defence being a reaction to the damage. This would of course be unrealistic and absurd, especially in the context of international conflicts where the first strike could be overwhelming. Rather, a limited degree of pre-emption is acceptable, to prevent a blow from falling in the first place.

The principle behind such pre-emptive action was set down in correspondence sent by the American Secretary of State, Daniel Webster, to the British Ambassador during the Caroline Affair of 1837. In his letter, Webster referred to the relevant necessity test in relation to self-defence as being where the need to take action is ‘instant, overwhelming, leaving no choice of means, and no moment of deliberation.’ 

Of course, attempts have been made in the years since this assertion was made to alter the strict interpretation of this approach. Perhaps most well-known of these was the assertions by the Bush administration in the US that the 2003 invasion of Iraq was predicated on the threat posed by Saddam Hussein’s regime’s possession of weapons of mass destruction. Becoming known as the ‘Bush Doctrine’, this highly controversial and largely rejected reinterpretation of the pre-emption principle into one of preventative action would have created a precedent for the sort of action we are seeing in Ukraine. However, military actions, including invasions of foreign nations, for the purpose of preventing the realisation of far off and vague threats has, thankfully, not been embraced by the international community at large, and remain outside of the accepted principles of international law. As such, any claim of an unrealised threat from NATO or Ukraine’s membership to it can hardly be relied upon to justify military action.

Even if Russia did have some genuine claim to taking defensive action against Ukraine generally, or in relation to the border regions, self-defence would not anyway allow for the unrestricted warfare on display. Rather, any genuine defensive action would need to be both necessary and proportional to the threat faced. That means that in response to a genuine and immediate threat, the action must be limited to the defensive goal of repelling the attack. That necessarily excludes wider actions to defeat an enemy nation completely, unless that is the only way to stop said attacks.

Looking at the early reports of the Russian action in Ukraine, it is even more clear that suggestions of defence are nothing but an attempt to justify the unjustifiable. Russia’s early actions have seen missiles striking targets across the entirety of Ukraine, in addition to the thousands of troops pouring across the country’s borders. This would be clearly excessive to an immediate defensive goal within the border regions, and would equally not be justified in the face of an established threat from the country’s potential membership to NATO. 

Alternative Justifications

Alternatively, claims have also been made about the status of the Eastern Ukrainian regions of Donetsk and Luhansk, which the Russian state have recognised as independent. This is similar to claims it made to explain its 2014 annexation of the Crimean region via a highly questionable referendum on the subject held in the context of a much more covert military intervention by ‘little green men’. Much like that, however, the validity of such declarations are dubious, to say the least. More than that, Russia’s suggestion that it is permitted to enter the region on the basis of peacekeeping presumably seeks to invoke the idea that they were invited, a slim exception through which States can legally intervene in foreign nations. Given that these regions cannot be considered truly independent according to any objective standard of assessment, however, such permission could only be given by the government in Kyiv, which quite simply has not been given.

Failing the acceptance of any action taken in relation to these regions of the Ukrainian state, the one final suggestion made by Russia has been that the Russian-speaking minorities residing in these provinces are facing genocide at the hands of Ukrainian forces. This claim would potentially place any military action within the realm of humanitarian intervention, or the more modern Responsibility to Protect principle. These similar concepts essentially allow for international action in extreme violations of human rights. Given that genocide is considered to be the worst human rights violation possible, such a situation would undoubtedly be within the remit of these controversial doctrines. Again, however, while there are troubling reports of abuses within the regions, committed by both Ukrainian and pro-Russian groups, there is no evidence that anything like a genocide is taking place. Indeed, Ukraine has recently submitted a case to the ICJ on this very matter in an effort to establish that no such genocide is taking place.


What we are witnessing in Ukraine is no more than the realisation of the aggressive ambitions of a nation’s leadership. Nothing that has been said by the heads of the Russian State in recent weeks have lent any kind of legitimacy to the actions taken in Ukraine, and the international response to this crisis will undoubtedly be watched carefully by other nations with similar ambitions. What will be needed is a clear and united approach which ensures that Russia’s efforts are not successful and that Ukraine’s territorial and democratic integrity are left intact. This is not only crucial for the peace and security of Europe and the world, but also for the continued viability of an international legal system built on crumbling foundations.

Andrew Jones

Dr Andrew Jones

Lecturer in Law

You can find out more about Andrew’s research through his Pure profile, which sets out his research interests, publications, and contact details. You can also find out more about Coventry University’s research through our dedicated research pages.

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