Ukrainian forces are preparing for an onslaught by Russia. Photo: Facebook

The existential threat hanging over the Ukrainian nation has lifted, but the outcome of the war still hangs in the balance.

Russia was defeated and has retreated from the north, leaving Ukraine’s government and the capital Kiev intact. Airborne and armored battlegroups withdrawn from that front have suffered considerable losses of life, materiel and reputation.

In the south, however, Russia has been victorious, achieving three key objectives.

It has taken the town of Kherson, which supplies water to Crimea. It has secured the Azoz Sea coastal corridor, linking Crimea to Rostov. And it has de facto taken the port and communications hub of Mariupol. All that remains to do is to liquidate the final pockets of resistance.

Now, as Russia’s battered battalion tactical groups (BTGs) regroup and reinforce, a mighty struggle on the eastern front – perhaps the key battle of this war – looms in the Donbas.

The fall of Mariupol should deliver Russian President Vladimir Putin’s “denazification” aim, an aim which gets massive coverage in domestic media. The far-right Azov Regiment, fighting furiously with its back to the wall, is trapped in the fortified Avozstal steel plant.

An encirclement battle to capture the entire Donbas could, in addition to granting Russia the soil of the industrial region, deliver the blood of Putin’s “demilitarization” aim – by trapping the Ukrainian Army’s main force in a giant kessel (cauldron) and destroying it in a Carthage-style battle of annihilation.

According to news media, artillery preparation has already begun in the east.

But while there is considerable media speculation that Putin seeks a decisive victory by May 9, Russia’s World War II Victory Day holiday, that timing may be unrealistic.

Russian commanders gearing up for the attack face significant climatic and manpower challenges.

German armored troops in action in Kharkiv in 1943, after cutting off overstretched Soviet units in the kind of counter-attack Ukrainian generals may be mulling in the Donbas. Photo: Bundesarchiv

World War II returns to Donbas

Ukraine’s Foreign Minister Dymytro Kuleba told NATO ministers on April 7 that the upcoming offensive will feature “World War II-style battles.” And indeed, between 1941 and 1944, northeast Ukraine and southwest Russia witnessed the greatest armored battles in history.

The largest encirclement battle of all time was fought around Kiev in 1941, when Hitler’s Wehrmacht inflicted more than 700,000 casualties on the Red Army.

Kharkiv was the site of multiple battles, notably in 1943, when, in an iconic counterstroke – “The Miracle on the Donetz” – the Wehrmacht counter-attacked and stabilized its front after the catastrophe of Stalingrad.

Later that year, the Kursk area, north of Russia’s Belgorod, was the site of the largest armored clash in history, a clash that reversed the tide of the war in the USSR, forcing the Wehrmacht into retreat.

Eastern Ukraine’s wide, open landscapes favor the kind of armored warfare beloved of the Russian Army’s telegenic exercises: Armadas of tanks, personnel carriers and self-propelled artillery surging across the country, under the cover of fleets of helicopter gunships and jet fighter-bombers.

Expectations are that the Russian Army will conduct this style of “deep operation.” The aim is to strike deep around the Ukrainian flanks, dislocating their defensive lines, surrounding them and wiping them out.

Ukraine is believed to field about 40,000 troops on the Donbas front. Well equipped with armor and artillery, they represent the most muscular corps at Kiev’s disposal. They have been fighting from extensively fortified positions on the area’s long-disputed Line of Contact, or LOC.

One Russian pincer is expected to strike northward from the south, from the Mariupol area or up the Dniepr valley. Another is anticipated to strike southward from the north, likely from the area of Kharkiv-Izium.

While this is underway, the Ukrainians will be fixed in place by the Russian separatists who have, since 2014, been fighting along the LOC for the self-declared republics of Donetsk and Luhansk.

If and when the pincers meet – it is unclear where that might be, a town or road junctions west of Donbas, or even further west on the Dniepr River – the Ukrainians, trapped, could be destroyed in detail.

That would “demilitarize” Ukraine, while granting the entire Donbas, rich in coal and iron, to the Russian Federation. This achievement, together with the acquisition of the Avoz coastal corridor, could satisfy the Kremlin, allowing it to declare victory, consolidate gains and begin peace negotiations.

However, for almost half of every year, cross-country maneuver operations are largely not viable. In spring and fall, Ukraine’s rich, black soil becomes a quagmire.

Ukrainian armored infantry in motion. Photo: WikiCommons / Adriana M Diaz-Brown / US Department of Defense

Armor versus mud

During the combat in the north, no TV footage of the kind of cross-country fighting seen in Russia’s dramatic exercises has emerged. The spring thaw channeled Russian BTGs onto tarmac.

Unable to maneuver off-road to bypass or surround urban centers, the BTGs fell to ambushes by Ukrainian infantry, drones and artillery.

And ongoing climatic conditions do not favor any Russian victory by May 9.

“In normal circumstances, mid to late May would be when you could expect firm ground for good cross-country operations,” said Prit Buttar, a military historian and British Army veteran who has written extensively on World War II combat in Ukraine.

“The [Russian] use of roads in the original invasion was predicated upon the belief that there would be little or no resistance. That clearly isn’t going to be the case going forward.”

Moreover, the Ukrainians have used an underreported tactic to exacerbate their terrain’s defensive qualities.

“The Ukrainians used their control of lock gates, dams etc, north of Kiev to flood large areas,” Buttar, who has traveled widely in the region, said. “And they may be able to do so again.”

Of course, mud does not entirely halt the cross-country movement of armored vehicles.

“A lot of Soviet-era vehicles have surprisingly good mobility off-road, so it doesn’t necessarily follow that poor soil conditions will create issues that cannot be overcome,” Samuel Cranny-Evans, an analyst with London-based military thank tank RUSI analyst, told Asia Times.

“If they select routes carefully and do not allow too many vehicles through the same area, there’s no technical reason that they will be unable to move off-road.”

However, “Marshal Mud” certainly slows an attack and creates logistic problems. “Supply may remain an issue as wheeled vehicles are generally worse off-road than a tracked equivalent,” Cranny-Evans said.

So if the Russian commanders want optimal conditions, their big operation may not be unleashed as soon as is widely expected.

Still, the Russians are expected to bring a better fight to the east than they did to the north.

“Russian units at the beginning of the war were not ready or supplied for heavy fighting,” wrote Jack Watling, a research fellow for land warfare with think tank RUSI, in a commentary for The Observer. “Now, the Russians appreciate what they are up against and with only two axes to support, can concentrate their supplies.”

Already, some 40 BTGs have been identified massing in the Belgorod area – a key communications hub with significant logistic and fuel depots close to the operational area.

Watling added that Russian air defenses have good coverage over the Donbas, and the offensive will be accompanied by the customary heavy Russian use of artillery. Given that the combat will be in rural, rather than urban areas, “Ukrainian troops will need to maneuver to survive,” Watling predicted.

However, the terrain is not simply open plains. It is far more urbanized than it was in the 1940s.

“This is a region with a lot of towns and cities, almost within tank gun range of each other,” Buttar said. “A swift thrust through the region is almost impossible without the complete collapse of the defenders.

“Consequently, I think that the Ukrainians will be able to fight a very effective defensive battle, falling back if needed from one town to the next,” he said.

A Ukrainian tank maneuvers in the Donbas. Photo: WikiCommons / UTR News

Boots on the ground

Major questions hang over the manpower both sides can deploy.

Amid a fog of both war and propaganda, there is no definite or reliable information on how many casualties either side has suffered. However, most indications are that the Russian BTGs that fought in the north suffered heavy casualties and losses of equipment – perhaps as high as 20%.

Russia boasts a massive armaments industry and a vast pool of armored vehicles to re-equip from. But when it comes to soldiers, commanders face constraints related to both Russian politics and the HR demands of warfare.

The Russian Army has been heavily reformed under current Defense Minister Sergei Shoigu, taking on ever-more professionals (kontrackniki). The upside is better quality soldiers, but the downside is that it is politically sensitive to deploy conscripts to expeditionary wars of choice, such as Syria and Ukraine.

Then there are the basics of wartime deployment.

“If an operation is going to drag on more than a few weeks (as it already has), the rough rule of thumb is that you can commit only one-third of available troops,” Buttar said. “Another third will be recovering from deployment in an earlier phase, while the last third trains and prepares for its turn in the theatre.”

Widespread estimates are that some 120-130 BTGs have already been engaged in Ukraine, of the 176 total BTGs the Russian Army fields.

“My understanding is that the troops committed to date are over 55% of the total strength of the Russian armed forces,” Buttar estimated. “This is not remotely sustainable in anything but the short term.”

And in the world’s largest country, there are other calls on military manpower.

“Even this means that you then effectively have no troops available for any unexpected emergencies that may arise elsewhere,” Buttar said.

The longer the Russians take to mass their attack, the longer the Ukrainians have to prepare a fiery reception.

“The Russian attacks in Donbas will largely be along predictable axes,” Buttar said. “The Ukrainians have plenty of time to deploy their best units in these areas and use their reservists or volunteers to cover their flanks.”

On the surface, the manpower matrix is shifting in favor of Kiev.

It has conducted a general mobilization, putting rifles into tens of thousands of willing hands. However, while reservists and militiamen may be able to defend static positions in and around hometowns, they may not be capable of mobile operations.

And the kind of complex, combined-arms maneuver warfare expected in the Donbas is challenging even for highly trained professionals.

This points to an inescapable fact of the Ukraine war. Though Ukraine is starting to hit targets across the border in Russia, the attackers still hold the initiative on the ground.

The kind of sweeping, off-road armored operations seen in Russian military exercises – such as this one – have been halted by Ukraine’s spring thaw. Muddy ground has channeled armored columns onto roads, where they are easy prey for Ukrainian defenders. Photo: WikiCommons / Russian Ministry of Defense

Once the offensive gets underway, the Ukrainians will want to attack the Russian northern pincer from its flanks and cut it off from its rear – thereby trapping the Russian spearheads in their own kessel.

If that fails, the defenders will be forced to carry out fighting withdrawals, attriting their attackers while avoiding encirclement and destruction – a hugely difficult form of fighting.

And what about victory? Can the Ukrainians maintain enough of a maneuver force to deliver the kind of punishing “backhand stroke” the Germans unleashed against onrushing Russians at Kharkiv in 1943?

“When the Russian attack runs out of momentum, that’s when the Ukrainians will need a mobile force to make a major counter-attack,” Buttar said.

Looking further ahead, if the Russians are unable to achieve a decisive encirclement, and the Ukrainians are unable to achieve a decisive victory, the war may drag on.

That could mean the kind of back-and-forth fighting that has prevailed along the Donbas LOC since 2014 – albeit on an expanded front on the Donbas, and on a new front in the south.

“The Russians want quick battles of annihilation,” predicted Frank Ledwidge, a lecturer in strategy at the University of Portsmouth on these pages. “What they will get is a war of attrition.”