‘The war in Ukraine is our war. It is everyone’s war... because Ukraine’s victory is a strategic imperative for all of us,” UK Foreign Secretary Liz Truss said last week.

“We are doubling down. We will keep going further and faster to push Russia out of the whole of Ukraine.”

With those words, Truss made it official. Britain may not be directly at war with Russia in Ukraine. But indirectly, it is most certainly in a Cold War, a proxy war. For the first time, the western alliance are publicly committed to Kyiv’s own war aims.

It is a dramatic shift. At the beginning of the war western governments were all but convinced Vladimir Putin would prevail.

So little faith did they have in a Ukrainian victory that they pulled their embassies out and refused to send heavy weapons that might fall into Russian hands.

The change of course crystallised in a series of announcements this week. On Wednesday, Lloyd Austin, the US defence secretary, convened a meeting of counterparts from more than 40 nations to cement an alliance to provide Ukraine with military support, telling reporters that “Ukraine can win”.

On Thursday, the Biden administration asked Congress for approval for a $33bn (€31bn) military aid package — a sum equivalent to half Russia’s entire annual defence budget.

On Friday, Congress approved a Lend-Lease act for Ukraine modelled on the plan that helped defeat the Nazis.

The American moves came alongside pledges of heavy weapons and assistance from other allies. Western governments, argues Keir Giles, an author specialising in the Russian military, are realising: “Russia is not going to stop until it is stopped.”

In other words, Ukraine’s allies not only believe it could win, but that it has to. But how? The shortest path to victory lies across the battlefield. In the imagination, it goes something like this: While resisting the Kremlin’s offensive in Donbas, Ukraine re-equips and retrains on the armour, artillery and air-defence systems pouring in from western allies.

As the Russian offensive peters out, Kyiv launches its counter-offensive. Ukrainian tanks rout Vladimir Putin’s over-extended troops and chase them back to the border.

The Kremlin, its army shattered and arms industry throttled by sanctions, has no choice but to come to terms.

But that, says Mark Galeotti, a veteran Russia watcher, is unlikely.

The Russian army may have botched its blitzkrieg. It may have problems with morale, logistics and leadership. But Moscow still has more men and guns, and has historically been very tenacious on the defensive. If it digs in on captured territory, the onus would be on the Ukrainians to find the 3:1 numerical advantage required for offensive operations.

If Vladimir Putin formally declares war — a step many expect on May 9 — he could raise conscripts from a population three times the size of Ukraine’s. Even with its new kit, a Ukrainian counter offensive to retake the swathes of Kherson, Zaporizhya, Kharkiv, Donetsk and Luhansk Oblast would be a tall order.

“The odds are we are not heading for a situation in which either Russia or Ukraine can deliver a knockout blow. So the question is where the lines are: will it freeze or not?” said Galeotti.

The second route to the Truss version of victory is a combination of military and economic attrition that becomes unbearable for Russia.

“That is about Russia’s capability to re-arm under sanctions. But it is also to lead to this revolution in the Russian elite’s mindset — that they cannot wage a war against the united West. They have never waged a war against a united West that they have won,” said Orysia Lutsevych, director of the Ukraine Forum at Chatham House.

How long it will take for that realisation to dawn in the Kremlin, no one knows. Some western officials speak in terms of years not months.

And time can work for both sides.

While the West hopes to grind down Russia economically, the Kremlin will be hoping to hold out until cracks appear in the western alliance.

“We see some alignment on those objectives between Eastern Europe, the UK, US and Canada, but there is still a gap with what Germany and France think,” said Lutsevych. “They have another view that we should not corner him or threaten Putin too much militarily with defeat. The big question is, how do you defeat a nuclear power?”

It is a reasonable question. How Putin would react to the prospect of defeat remains a central concern. He has made reference to using nuclear weapons, but exactly when he might resort to them remains ambiguous.

Margarita Simonyan, a loyal propagandist, suggested the threat of defeat would do it. “Either we lose in Ukraine or the Third World War starts,” she told Russian Television. 

© Telegraph Media Group Ltd (2022)

Telegraph Media Group Limited [2022]