Here we are, in our ringside seats at a bloody circus, watching on TV and Twitter, trapped between infinite pity and rational self-interest. The tension between two opposing forces is unbearable. Pulling from one side, our horror at a senseless invasion, our wonder at the Ukrainian resistance, the unarmed villagers mobbing a Russian tank or feeding a captured Russian conscript sobbing as he is allowed to phone his mother, and our sorrow at the sight of terrified children in the bunkers huddling against their parents while their towns are destroyed; and from the other, waiting outside Kyiv, the 40-mile column, which we know could be destroyed in an afternoon by satellite-guided cruise missiles and stealth jet fighters invisible to radar. The unlockable buckle restraining the west is fear of nuclear war, and Vladimir Putin, elevated into a deranged and unpredictable adversary, has played us well. So we are strapped in place by a bluff we dare not call, expert watchers with the mouse clicks and screen swipes, and in our communal anguish, incapable of much beyond sanctions and arms donations, alms and fulminations. At each stage of the long Russian buildup of forces around Ukraine’s borders it was Putin’s privilege to call the next move and the west’s to respond, which, game theorists will insist, is weak play. The strong hand first seeks cooperation, then, when failing to get it, comes back hard with raised stakes. But Nato is not a single player, it’s a crowd of 30; and when groups make decisions, they tend to moderation. There are ghosts in the circus ring. In 1914, European nations protested peace as they “sleepwalked” into war. They got there by slow steps, unhindered by nightmares of nuclear winter. Now we are forced to interpret the tainted neural processes of one man and his sickly dreams. This is the ultimate “madman” sanction in nuclear tactics; if you cannot rely on your opponent to act logically to his own advantage, you are frozen in place, waiting for his next move, unable to take risks by direct intervention. There are younger ghosts in the ring in the form of Grozny, Aleppo and Idlib. There the Russian calculation was to destroy from the air hospitals, triage clinics, residential blocks and schools in order to demoralise the population. In Ukraine, as Russian troop movements falter, the same cruel tactics are beginning to be repeated. There has always been a special dispensation for artillery units denied to “poor bloody infantry”. As they lob their shells across the landscape with fine regard for the mathematics of parabolic curves, artillery soldiers need never look into the eyes of a dying child. The same goes for guided missiles, and for bombs “aimed” from military planes. Murder at one remove is a simpler, more abstract crime. Ordinary Russian conscripts have no such luxury of dispassion. Those who have been captured or have surrendered appear spectacularly ill-informed about their mission. They are amazed by their lack of welcome on Ukrainian soil. If they are extremely lucky, they are overwhelmed by the kindness of locals. They are ill-served by their lines of supply, often disrupted by Ukrainian forces using anti-tank weapons against transport trucks and petrol tankers. For all the talk of a modernised Russian army, ordinary soldiers appear to be treated like serfs. That fearful column outside Kyiv may be regrouping and preparing to strike or it may be an emblem of all that has gone wrong on the Russian side. With only five days’ supply allotted to each vehicle, the troops may be hungry, thirsty, short of fuel and, most vitally, of motivation to kill fellow Slavs. We will soon find out which it is. The paradox is that the more Russia fails in the field, the more Ukraine has to fear from dispassionate shelling. There seems no way out, for a dazzling Russian military success would be Ukraine’s nightmare too. Grim success may be the more likely outcome. Kherson has fallen, Mariupol is under heavy pressure, Odesa may be next. Ukraine could soon be overrun. Recent history assures us of the capacity of the Russian command to allow atrocities on a colossal scale. For all our pity and anguish, our status as onlookers is luxurious. We have enjoyed moments of clownish light relief as chortling farmers on tractors steal a tank or a bemused passing motorist offers to tow an armoured vehicle back across the Russian border. For now, in the west, thoughts are mostly on punishing Russia. Symbols preoccupy us. An orchestral conductor is sacked from his roles in Edinburgh and Munich. Football matches are cancelled. Oligarchs’ yachts have been seized. Beyond these important tokens, only financial sanctions really bite, and they have been impressive. But even as his economy crashes, Putin seems to have persuaded himself he can, in the celebrated formulation of Tacitus, make a desert and call it peace. It is painless to order up slaughter and destruction in the grisly security state over which he presides. If nothing changes in the Kremlin, the collective minds of the international community must turn to solutions, for the added danger is of conflict spillover – as powerful weaponry from Europe and the US flows across the Polish border into Ukraine, it could become convenient for Putin to decide that he is at war with Nato after all. On behalf of all of us who root for Ukraine, some creative thinking is required beyond symbols, punishment and rearmament. It should not be left to ad-hoc face-offs of the belligerents in a hut on the Belarus border. It does not look hopeful. Ukrainians are in an existential struggle for the country they love. Putin believes he is bound to prevail. Between the “eastward expansion of Nato” and the “right of a sovereign state to decide its arrangements” there may appear to be no compromise. But all brokered cessations of hostilities begins with such irreconcilables. A sophisticated, if not sophistic diplomatic culture that includes China should now be straining all its resources to devise, as a minimal first move and with all the ingenuity and compassion it can muster, the terms of a ceasefire. Without the attempt we will be condemned to watch mass death up close – and we will never forgive ourselves. Ian McEwan is a novelist and screenwriter. He has donated the fee for this article to the Disasters Emergency Committee