This year a scattering of missiles, carefully directed at the energy distribution networks that make life bearable in the freezing weather, accompanied the early snowflakes. Moscow is doing everything it can to intensify pressure on Ukraine to accept the status quo, begin negotiating, and legitimise the Russian seizure of the huge swathe of land along the Black Sea coast to Crimea.

Volodymyr Zelensky now faces a simple quandary. His forces are exhausted after fighting through to Kherson, on the west bank of the Dnieper (Dnipro), the river bisecting Ukraine. Does he accept the unbearable and give Vladimir Putin what he wants? Or does he continue fighting now and attempt to capitalise on the success of his forces in wresting territory back from the retreating Russians?

The urge to continue fighting is intense. It is just 95 days until the one-year anniversary of the invasion. Normally - from the wars of the 18th century and through to the Second World War - this period of freezing cold would send the troops into winter quarters as it was impossible to motivate soldiers to fight. Now, after the months of bitter fighting that have already taken place, Zelensky is asking his forces to again assault well-prepared Russian defensive positions, simply in the hope of creating a better position at the bargaining table. His problem is this winter offers the best chance Ukraine has to reverse the successful fait accompli created by Putin's successful assault. A failure to fight back and regain territory by that time risks entrenching lethargy.

Both sides want the war to end; the only question is where to locate the borders. A lot of lives will still be lost while we wait to discover the answer.

What's prompting the continued Ukrainian offensive is the current military position. The small explosion on the road bridge across the Kerch strait to Crimea has significantly changed the operational dynamic. New possibilities for an assault have opened up, with the possibility of cutting-off the advanced Russian spearheads which now rely on a single 300km-long road for their resupply. This stretches along the Black Sea coast through Mariupol and is the only good east-west link to Moscow's forces on the east bank of the Dnieper, and all their ammunition and food has to travel the 300km along this link. If this could be completely cut, they'd be utterly exposed with no alternative but to retreat or surrender.

This is Zelensky's opportunity. It's his last, perhaps only, chance to change the situation on the ground.

Although they've been reinforced, Russian forces are now stretched in a thin crust along the front. All reports suggest morale is not high and the conscripted forces are reluctant to leave the safety of their dug-in positions. A strike south to the sea along a medial route offers the prospect of cutting the laterals, increasing the chance of a defensive zone suddenly dissolving and the Russians pulling back in chaos, as occurred a couple of months ago to the west of Donetsk. Although that front has now been stabilised by the Wagner group, the mercenaries have had little success throwing the well-equipped Ukrainians back.

Such tactical methods would be very familiar to the officers on both sides who served in the old Soviet army. Commanders then were taught to look for opportunities to send tank-heavy, operational manoeuvre groups striking deep into the vulnerable rear of their enemy and dislocating enemy command structures. A sudden, deep thrust like this is not impossible and represents Zelensky's best chance. But Putin isn't going to make it easy.

The Russian leader has stopped pulling recruits off the streets of his cities and forcing them into uniform, but this doesn't show any lack of determination. Putin's deepest beliefs are revealed in a weird, inaccurate and confected 5000-word essay, published on his personal website in July, 2021. This insists the inhabitants of both countries are "one people", or narod, who only became separated after the Mongol invasions and successive Western plots to weaken the historic destiny of Russia. The thesis is so extremely wacky it obviously actually reveals the dictator's innermost beliefs, simply because nobody could make it up.

Putin hasn't engaged in this war simply because he thought he could easily grasp an extra slice of land to annex to mother Russia - he genuinely believes he is reversing a historical wrong. He is not rational and cannot be expected to react logically to defeat on the battlefield. Neither what's occurring on the battlefield or the increasing economic difficulties on the home front have succeeded in denting his obsession with bringing this war to a successful conclusion. It's difficult to see how even a significant military victory would change this calculus, particularly as Putin is that most dangerous of all madmen: one with nuclear weapons.

In the meantime he's determined to continue fighting in the only way he can. By using missiles to destroy infrastructure, Putin believes he can make life so terrible for ordinary Ukrainians they will demand Zelensky finally caves in and asks for a ceasefire. This would stop the war, but it would also cement the front line where it is today. While this would not give Putin all he wanted at the start of the fighting, it would offer him enough to justify his 'special military operation'.

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This is why Ukraine needs a quick and decisive battlefield victory before winter sets in.

Zelensky needs to work on the minds of the people around Putin. If these people can be convinced to tell the Russian dictator there is no point continuing the fight, there's a chance the Russians can be dragged to peace talks.

To do this he needs a victory on the ground. Now.