Ukraine may be cracking Russia's frontlines, but now it has to get Russian troops to crack as well

• Ukraine's counteroffensive has begun piercing Russia's defensive lines.
• But Russian troops have been fighting fiercely trenches behind extensive obstacles and minefields.
• To really break through, Ukraine will have to get the Russians out of their trenches and on the run.

Ukraine's counteroffensive is slowly piercing Russian defenses, at great cost in casualties and time. But if Kyiv wants to avoid a grind in which a successful attack is limited to capturing an obscure village or taking a few hundred yards of territory, it has to get the Russian army on the move.

To do that, Russian troops must be compelled to retreat from their elaborate fortifications — widely known as the "Surovikin Line" — out of fear of being surrounded and annihilated or at least cut off from resupply and reinforcements. Once the Russians are forced into the open and engaged in mobile warfare, the more tactically nimble Ukrainian troops might be able to destroy them.

It's a strategy that Nazi Germany used with some success against the French in 1940 and the Soviets in 1941, but it's easier said than done. Ukrainian troops have managed to penetrate the first of three Russian fortified belts in southern Ukraine, but for now, the Russian military hasn't cracked.

"If Russian units can be forced to reposition, however, the poor training and discipline of Moscow's forces could see the defense become uncoordinated and susceptible to collapse," experts with the Royal United Services Institute, a British think tank, wrote in a report released in June, as the counteroffensive was just beginning.

To aggressive commanders like Gen. George Patton — who called fixed fortifications "monuments to the stupidity of man" — an army that remains entrenched is an army that has handed the initiative to the enemy.

Yet fortifications can also be a powerful force multiplier. While the Maginot Line is remembered as a fiasco, it was actually a reasonable way for France to economize on scarce manpower and free up troops for other sectors of the line.

A similar dynamic seems to be playing out in Ukraine today. Russian troops are dug into elaborate trench systems shielded by millions of mines and supported by artillery and attack helicopters. They have inflicted painful losses on Ukrainian assault brigades that are still learning to use their newly adopted Western tactics and armored vehicles.

Second-rate French divisions also inflicted heavy losses on German assault troops attempting to cross the Meuse River at the Battle of Sedan in May 1940. While the French high command dithered, the battered defenders at Sedan eventually cracked, creating a hole that German armor swiftly exploited.

At that point, the campaign became a mobile field battle, which the rigid French command-and-control structure was unable to cope with. France — considered one of the strongest military powers in the world — surrendered in just six weeks.

The accusation that French troops were cowardly is unfair. They often fought hard and bravely, but traumatized by the grievous losses of the First World War, their morale proved brittle. "Again and again I have heard from tired, beaten, soured French soldiers the bitter words: 'We were betrayed. The politicians sold us out,'" an American journalist recalled at the time.

The echoes with Russia in 2023 are eerie. Russian soldiers frequently complain of incompetent commanders who callously sacrifice them in futile attacks. "Disposable infantry" composed of prison inmates and reluctant conscripts are not likely to perform well during a retreat, perhaps the most stressful of military operations.

Russian morale is "low, with a rise in prosecutions for desertion, observed instances of wounded comrades being abandoned, and very little depth of junior leadership," the RUSI report noted. "Personnel are also rarely rotated and there is considerable weariness across the force."

Nonetheless, despite hopes that Russian morale would collapse under Ukrainian assault, this hasn't happened on any significant scale. In theory, these problems "should make Russian units brittle," the report said. "In practice, they appear to be able to take very heavy punishment without collapsing. Instead, morale problems appear to manifest in poor cooperation within units and even less between them."

The good news for Ukraine is that Russian forces suffer from "a tendency for coordination and cohesion to fracture under pressure," the report added. "This is likely to make Russian units underperform in defense if they can be forced to move or engage in a dynamic action."

But as the report admits, morale is the "critical and yet most elusive variable in assessing the strength of Russian military units." Russian defenses in Ukraine may yet crack — but no one can be sure when.

Michael Peck is a defense writer whose work has appeared in Forbes, Defense News, Foreign Policy magazine, and other publications. He holds a master's in political science. Follow him on Twitter and LinkedIn.