Before assessing the current state of the Russia-Ukraine war, it’s worth revisiting some theory and history.

The concept of deep battle (not to be confused with a deep operation) refers to the rapid penetration of a defensive line across its full tactical depth. In modern conditions, this depth usually extends 15-20 kilometers from the forward edge of the front line.

The notion of deep battle first emerged toward the end of WWI. Between March and July 1918, Germany conducted a series of offensives on the Western Front that for the first time demonstrated how to break through entrenched defenses using concentrated artillery fire on critical nodes (machine-gun nests, mortar positions, and artillery emplacements) followed by fire shifting deeper into the enemy rear. Assault teams would then infiltrate past resistance points, encircle them, and allow regular infantry to clean up behind.

The Allies employed similar methods in their “Hundred Days Offensive” (August-November 1918), but with a notable innovation: tanks. These armored vehicles added much-needed tactical mobility, albeit still within tactical depth. 

The deep battle of 1918 never matured into a full-fledged deep operation. Two key limitations held it back:

First, armies lacked reliable means of tactical mobility to operate deep behind enemy lines — to disrupt command structures and supply chains at scale. Tanks, still in their infancy, had not yet evolved into the breakthrough weapon they would become in the interwar years.

Second, most artillery systems had limited range (typically under 10 km) forcing repeated halts to re-aim guns. This gave defenders enough time to regroup and build new defensive lines. The result was a cycle of stalling advances and missed opportunities.

As a result, both the German offensives and the Allied advances in 1918, although based on the concept of deep battle, took the form of pushing the enemy back rather than encircling and destroying its main forces.

The very term deep battle was coined by Soviet military theorists in the 1920s and 1930s to describe a qualitative breakthrough of the tactical defense along its entire depth — a phenomenon first demonstrated in 1918, though not yet developed into a full operational concept.

What we are now seeing on the Russia-Ukraine front line is the emergence and widespread use of various types of drones and guided aerial bombs, which have made it possible to effectively isolate the front line from reinforcements, logistics and medical support.

This dynamic was first clearly described by RUSI analysts in a February 2025 report. The resulting “drone wall” extends up to 15 km deep, and, unfortunately, it works both ways. Compounding the problem, Ukraine's severe shortage of personnel has made it easier for Russian forces to bypass defensive strongpoints along the frontline. All this lays the groundwork for positional pressure and gradual pushing rather than breakthrough.

These trends became apparent in 2024 and remain in place today. Ukraine lost 3,600 square km of territory over the course of 2024. In January-February 2025 alone, nearly 2,400 square km have been lost, with 1,570 square km falling to Russian forces between May and July.

The pace of deep battle remains limited by the presence of symmetric technologies. While the enemy attempts to sever Ukrainian frontline positions from their rear, Ukrainian defense forces try to cut off Russian assault units from their own supply lines, targeting them at standoff distances before they can engage troops at the zero line. In addition, the enemy can’t isolate Ukrainian positions from the rear all at once. The process is staggered over time, turning into a war of attrition. This, combined with infiltration tactics, forces Ukraine to carry out tactical regroupings.

No sweeping conclusions follow from this. Except that without stabilizing the front line, it is hard to imagine negotiations with Russia based on compromise rather than diktat from the Kremlin. Meanwhile, the battlefield dynamic that became evident in 2024 continues: Russia has not been able to translate tactical gains into large-scale breakthroughs, but Ukraine has also been unable to fully stabilize the front.

Photo credits: Suspilne / Oleksandr Sova