One of the greatest English poets of the 20th century, Philip Larkin, wrote a two-line satirical poem in 1969 criticising the then British governments’ defence policy. It ran “When the Russian tanks roll westward, what defence for you and me? Colonel Sloman’s Essex Rifles? The Light Horse of the L.S.E.?”.

The Russian tanks never rolled westward then but they have now.

It is apposite to refer to Larkin’s poem given it was written right in the middle of the Cold War, 20 years after the Berlin airlift and 20 years before the demolition of the Berlin Wall. Today’s Russian military attack on Ukraine is partly, at least, attributable to how the Cold War ended and the immediate aftermath of that end. Conflicts such as the Russian invasion of Ukraine have both deep-rooted causes or what historians refer to as the longue durée, as well as immediate triggers or contingent factors. If the conflict is to be truly resolved, one needs to address both.

The century-old enmity between France and Germany was not resolved only by the military defeat of Nazi Germany but chiefly by the wisdom and courage of those who sought to remove the root causes of the conflict such as Jean Monnet, Robert Schuman and Konrad Adenauer with their creation of the European Coal and Steel Community and the ever closer union between their economies and their people.

The collapse of the Soviet Union and then the end of the Cold War in 1989-91 was an opportunity for Europe to reimagine and restructure its security architecture; an opportunity to treat Russia as a key partner and ally in ensuring security and cooperation across the European continent as a whole.

The US approach and wider NATO approach at the time was to expand and effectively isolate in the security sector the Russian Federation. Or at least this is how it was seen and how it is perceived in Moscow. And as those involved in resolving conflicts know only too well, perceptions matter more than reality.

At various points, some efforts were made to bring Russia in the fold of a shared security arrangement. Possibly, the high point of these efforts was the 2002 NATO-Russia summit at Pratica di Mare, Italy. However, the 2002 agreement never took off fully and NATO’s eastward expansion and President Vladimir Putin’s increasingly assertive foreign and military policy led to increasing tension rather than détente.

At the psychological level, the collapse of the Soviet Union also plays a role in today’s Russian aggression. Putin himself was a KGB operative in Berlin at the time of that collapse and in his autobiography, he recounts how he was busy burning secret files to avoid them falling into the hands of the victorious West.

It is no surprise that he referred to the collapse of the Soviet Union as the greatest calamity of the 20th century. This psychological trauma and feeling of humiliation for many Russians plays a part in today’s tragedy in Ukraine.

These structural and psychological root causes of Russia’s militarism today explain part of the tragic events of last week.

They certainly do not excuse Putin’s flagrant act of aggression towards Ukraine. It is a blatant and grave breach of the most fundamental principle of the United Nations Charter and of international law generally. It is also a crime under international law, which alas will remain unpunished.

The international community should unite in condemning Putin’s aggression and take all necessary measures to ensure that military aggression does not succeed.

If the Russian invasion of Ukraine is successful in terms of annexing even more Ukrainian territory and in installing some kind of puppet regime in Kiev, the whole basis of international legal order established since 1945 will have been buried forever.

The imposition of strong financial sanctions on those responsible, as well as supporting Ukraine’s inherent right to self-defence, is imperative for the longterm survival of some sort of international legality. However, even a successful defence of Ukraine’s territorial integrity is insufficient to guarantee long-term peace.

To achieve that elusive positive peace, NATO and the EU in particular need to fundamentally reassess and reimagine the relationship with Russia. Such a structural rethink is critical to secure longterm peace after whatever transpires in the next dark days and weeks.

Omar Grech is director of the centre for the study of conflict resolution at the University of Malta.