YESTERDAY, as MPs in Westminster squabbled over parties, the future of European civilisation was hanging in the balance as Russian troops moved to annex the Donbas region of Ukraine.

Vladimir Putin’s forces advanced across the entire 300-mile front line along the Donetsk, Luhansk and Kharkiv regions.We haven’t seen land battles like this in Europe since the Second World War. We never though we would see them again.

If Putin’s imperialist adventure succeeds in Ukraine, no country in Europe will be safe. It will alter the strategic balance of the continent and begin a new Cold War – and probably a hot one as Nato mobilises the anxious nations on Russia’s border. The stakes could not be higher.

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At the sharp end, in ruined Mariupol, around 1500 diehard Ukrainian defenders have offered their lives to prevent Russia declaring victory in that crucial coastal city. Holed up in the Azovstal steel works, they defied a Russian ultimatum on Monday to surrender and be spared.

It may seem utterly futile. A waste of lives. They can’t possibly hold out much longer in this ruined city against overwhelming odds. But they evidently don’t see it that way. Ukrainians keep being told that they are beaten and they keep refusing to accept defeat.

President Zelenskyy has galvanised his nation into an extraordinary defence against Putin’s war of aggression. He has become a modern Churchill who has “mobilised language and sent it into battle”. And he has not allowed us elsewhere in Europe to conveniently forget about Ukraine’s fight. To return to normal domestic politics and the petty rows that inflame social media. To shrug and accept that might is right, and that the Ukrainians should be “realistic”.

Mariupol will go down in history as other pivotal battles, like Stalingrad in 1943. The longer the handful of subterraneans survive in the networks of tunnels and bunkers under the steel plant the more moral pressure will be applied to Nato to increase arms shipments.

The 2001 film Enemy at the Gates, about the battle of Stalingrad, gives an impression of what life must be like in the steelworks. It is dirty and personal. Hand to hand fighting over metres rather than miles. Yet this time round, unlike in Stalingrad, the Russians are the enemy not the allies. And ironically the Ukrainian defenders in Mariupol include members of the far right Azov brigade – a force that used to celebrate the defeats inflicted on the Red Army by the Nazis 80 years ago.

This is why Putin claims this to be a war against fascism. Why his “special operation” is about “denazification”. President Zelenskyy insists that the Azov militias, which formed in Donetsk and Luhansk after the Maidan protests in 2014, have already been fully denazified and integrated into the Ukraine army. We don’t have to take his word for it. For if they are fascists, they are fighting for a Jewish President and to save democracy.

Azov has been fighting Russian-speaking separatists in the Donbas for seven years. Atrocities have been committed on both sides. A fire that killed dozens of pro-Russian separatists in a trade union building in Odessa in 2014 has been blamed on Azov.

But in a war of survival, in which Ukraine is now engaged, you can’t be too picky over who does your fighting. If Asov are prepared to give their lives to free Ukraine from a brutal invader, who has defied all standards of civilised conflict, then it is not up to us to question their motives. Whatever crimes were committed in the Donbas in a bloody civil war, they are as nothing compared to the near-genocidal behaviour of the Russian invaders.

You only need to look at the drone footage of streets lined with the blackened stumps of what had been apartment blocks in Mariupol. The Russians have deployed the heartless and illegal style of warfare they perfected in Aleppo and Chechnya. A war of elimination with no thought for the fate of civilians. It is not known how many have died in Mariupol, but it may well be in the thousands. It is hard to imagine anyone surviving in that ruined city that once housed 300,000 people.

Yesterday, Nato leaders discussed how to step up arms shipments to Ukraine. Britain and America continue to be in the forefront providing armoured cars, more anti-tank and anti-aircraft missiles. Some helicopters too. Poland has donated a few tanks.

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The trouble with this piecemeal approach is that it gives Ukraine the power to resist but not to win. Ukraine has withstood the first, rather chaotic wave of the Russian invasion. But now, after the humiliation of losing his Black Sea flagship, Moskva, Putin is going all in. He must force a victory before the May 9 victory parades in Red Square.

The West will shortly have to decide whether it seriously wishes to stop him annexing the Eastern Donbas region, where he can rely on the support of at least some of the Russian-speaking population. There are still many in the defence community, like the military historian Max Hastings, who insist that the only reasonable solution, the one that will save most lives, is for Putin to be permitted to annex Donbas.

This is essentially the view also of Stop the War and left wingers like Jeremy Corbyn who believe Nato expansion in Eastern Europe is largely to blame for the war. They seem to think that that Putin would then accept Ukraine neutrality and everyone could go back to the old normal.

But it is naive to think that this Russian leader would forgive and forget if he gets his territorial prize. It is even more naive to believe that President Zelenskyy and the rest of Ukraine would agree to be partitioned. Too much blood has been spilt, too many children killed, too many cities destroyed for relations with Russia to go back to normal.

It is now Nato that will decide the outcome. Either it provides the artillery, armour and jets that Ukraine needs. Or this war will go on and on, until Ukraine runs out of lives. It is decision time for the West.

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