Case study War in Ukraine

On 24 February 2022, Russia invaded Ukraine. One theory that seeks to explain Putin’s actions stems from the school of offensive realism in International Relations (IR), which holds that states are aggressive power maximisers trying to extinguish any threats to their security. Promoting this approach, Professor John Mearsheimer (University of Chicago) claimed at a recent talk at the EUI that Russia had no choice but to invade Ukraine. The neighbouring country presented an existential threat to Russia because of its Western ties. 

The world’s leading “realist” scholar of international relations, which argues that a state’s priority is being more powerful relative to its neighbours to ensure its survival, Mearsheimer had been warning of a possible Russian attack on Ukraine since the 1990s. In one essay, “The Case for a Ukrainian Nuclear Deterrent” (1993), he wrote that the West’s attempt to press Ukraine to become a non-nuclear state was a huge mistake. 

Liberal commentators contend that the Russo-Ukrainian War was an act of unprovoked aggression that can be explained solely by reference to pathologies with the Russian state, elite, and/or society rather than a response to a perceived external threat from the West. 

Prof Mearsheimer of the University of Chicago,  gave a lecture 2023- at the EUI's Robert Schuman Centre, argues that Russia had no other choice but to attack Ukraine following aggressive behaviour by the United States and Europe, driving Ukraine, Georgia and other countries on the Eastern flank towards NATO and EU membership. 

The war also illustrates another classic realist concept: the idea of a “security dilemma.” The dilemma arises because the steps that one state takes to make itself more secure often make others less secure. State A feels unsafe and seek any ally or buys some more weapons; State B gets alarmed by this step and responds in kind, suspicions deepen, and both countries end up poorer and less safe than they were before. It made perfect sense that states in Eastern Europe wanted to get into NATO (or as close to it as possible), given their long-term concerns about Russia. But it should also be easy to understand why Russian leaders—and not just Putin—regarded this development as alarming.  

The war is also evidence of the failure of institutions and the theory of interdependence international law and international institutions have proved to be a weak barrier to rapacious great-power behavior. Economic interdependence did not stop Moscow from launching its invasion, despite the considerable costs that it will face as a result. Soft power couldn’t stop Russia’s tanks, and the U.N. General Assembly’s lopsided 141-5 vote (with 35 abstentions) condemning the invasion won’t have much impact either. The war has demolished the belief that war was no longer “thinkable” in Europe 

'I think all the trouble in this case really started in April, 2008, at the nato Summit in Bucharest, where afterward nato issued a statement that said Ukraine and Georgia would become part of nato. The Russians made it unequivocally clear at the time that they viewed this as an existential threat, and they drew a line in the sand. Nevertheless, what has happened with the passage of time is that we have moved forward to include Ukraine in the West to make Ukraine a Western bulwark on Russia’s border. Of course, this includes more than just nato expansion. nato expansion is the heart of the strategy, but it includes E.U. expansion as well, and it includes turning Ukraine into a pro-American liberal democracy, and, from a Russian perspective, this is an existential threat.'  

Professor John Mearsheimer


The journalist Anne Applebaum accused Mearsheimer of being Putin’s useful idiot, tweeting that his article had given the Kremlin its talking points for the war. 

John simply can’t explain Russian behaviour because he is too focused on the international system and ignores the domestic forces at play. He suggests that Ukraine was about to join Nato, but it wasn’t, and he seems to find it reasonable to deny Ukraine the right to chart its own course. He also can’t detect Russia’s colonial attitudes towards Ukraine. I would consider myself a realist, but it is a realism based on assessing the situation as you find it rather than how you wish it to be based on some dogmatic theory.” 

Lawrence Freedman