When Russian troops and armoured vehicles entered Ukrainian territory on 24 February 2022, Europe moved into an unpredictable new era that tore apart established certainties and shattered peace and stability. The Russian invasion began an extended war that has cost thousands of lives, laid waste to much of Ukraine and unleashed the biggest movement of people out of their homeland for nearly a century. Since it began, the war has dominated daily media reports, political debate and countless international meetings. The rest of Europe watched in admiration as Ukrainian armed forces and citizens contained the Russian attack. The horrors of Russian violence have shocked and roiled the European continent.

The war is a tragedy for Ukraine, but also represents a transformative challenge for the whole European order. Beyond the atrocities and the shifting day-to-day dynamics of battle, Russia's conflict in Ukraine has profound implications for European politics and security. Alongside the human suffering and violence, the war invites searching questions about the whole way in which European security, politics and economics are organized. The war is not simply one stand-alone conflict but has structural and continental ramifications. What can be referred to as the “European order” has been shaken to the core.

At this level, the invasion was as momentous as it was shocking. Even the most knowledgeable and respected of analysts and politicians believed such an invasion to be beyond the realms of possibility. And when the invasion did begin, the same observers almost in unison could see no outcome other than a swift Russian occupation covering most of Ukraine. European governments had to scramble to adapt to Ukraine's sterner than expected resistance. Moreover, the war is not only game-changing in itself but has also unleashed or deepened many related challenges: the extent to which the war has affected so many areas of international politics, energy policies and economic trends has added further layers of concern across Europe. The outbreak of war and the events that have happened since have opened a Pandora's box of spill-over troubles.

While analysis has understandably focused on the war itself, this book examines these more structural and longer-term consequences for Europe as a whole. The most pressing policy question for European governments has been whether their support for Ukraine has been sufficient decisively to impact the immediate course of war – and as the conflict continues this question remains disconcertingly open.