Russia’s invasion of Ukraine shows, once again, that seismic shifts in the international order are inexorably followed by war. The adjustment invariably involves a declining power – in this case Russia, following the collapse of the Soviet Union – and a rising power – the West. So are we on the brink of a wider conflagration? Or might Putin’s war result in a return to some semblance of peace, if a treaty between Ukraine and Russia can be thrashed out?

Whatever happens, one thing has become clear in recent weeks: the Cold War ‘defeat’ of the Soviet Union – albeit morally not militarily...