Giorgi Koberidze

Assistant professor of International Relations

GIPA – Georgian Institute of Public Affairs

Tbilisi, Georgia

This article discusses the concept of strategic depth in military defense strategy and how it applies to Ukraine. Strategic depth refers to the distance between the front lines of a conflict and the rear, where a country’s vital assets such as population centers, industrial areas, and political centers are located. The idea behind strategic depth is to create a buffer zone that allows a country to absorb the initial shock of an invasion and conduct a prolonged defense. Ukraine has enough strategic depth to continue military activity without notice and receive Western aid practically unhindered. The country’s large population and well-developed infrastructure and industrial base provide sources of manpower and resources for defense. Additionally, Ukraine’s history of industrialization and modernization also means that it has a relatively well-developed infrastructure and industrial base, which could be mobilized for the defense of the country. Ukraine’s terrain also presents some challenges when it comes to strategic depth, but it also has some strategic depth in the form of its large population, which provides a source of manpower for the military.

Keywords: Military defense strategy, Prolonged defense, Defense in Depth, Multiple layers of defense, Western aid, Terrain

General overview

Any war’s Achilles heel is logistics. The logistical challenges for military forces entering adversary territory with strategic depth are exacerbated. Ukraine is one of Europe’s largest countries. Under the current challenges, it has enough strategic depth to continue military activity without notice and receive Western aid practically unhindered. States with strategic depth can move or hide their industry into the safe area, train their military, and engage in other military-economic activities without incurring huge losse. When using a military defence strategy like Defense in Depth, strategic depth becomes even more important. This was one of the main reasons why Kyiv effectively defend itself from Russia’s invasion.

Strategic depth

Strategic depth is a military concept that refers to the distance between the front lines of a conflict and the rear, where the country’s vital assets, such as population centers, industrial areas, and political centers, are located. The idea behind strategic depth is to create a buffer zone that allows a country to absorb the initial shock of an invasion and to conduct a prolonged defense, with the goal of ultimately defeating the enemy.

One of the key advantages of strategic depth is that it provides time for the country to mobilize its military and civilian resources, including its population, for the defense of the country. This is particularly important for countries with a large population, as it allows them to use their numerical advantage to their advantage. Additionally, strategic depth allows a country to make use of its natural terrain and geographical features, such as mountains and rivers, to create defensive barriers that can slow down or stop the enemy’s advance.

Another important aspect of strategic depth is that it allows a country to conduct a defensive war on its own terms. This means that the country can choose where and when to fight, and it can also choose the type of warfare that it wants to employ. For example, a country with strategic depth can choose to fight a guerrilla war, which is characterized by hit-and-run tactics and the use of small, mobile units. This type of warfare can be very effective in tying down a larger and better-equipped enemy force.

Furthermore, strategic depth also plays a key role in the psychological aspect of warfare. The enemy would have to fight in a foreign territory, far from their home, and they would have to fight against a population that is motivated to defend their country. This can create a sense of isolation and despair among the enemy soldiers, which can lead to low morale and poor performance on the battlefield.

Ukraine’s terrain also presents some challenges when it comes to strategic depth. The country is mostly flat, which makes it difficult to use natural features, such as mountains and rivers, to create defensive barriers. Additionally, much of Ukraine’s population and economic activity is concentrated in the western part of the country, close to the border with Poland, which leaves the eastern regions relatively thinly populated.

That being said, Ukraine does have some strategic depth in the form of its large population, which provides a source of manpower for the military. Additionally, Ukraine’s history of industrialization and modernization also means that it has a relatively well-developed infrastructure and industrial base, which could be mobilized for the defense of the country.

Because the Ukrainians had located the majority of their military units and equipment far from military bases and airstrips at the start of the war, it was able to save the majority of them from the first day cruise missiles. The Russian armed forces could quickly penetrate Ukraine if it weren’t for the strategic depth, forested terrain, swampy soil, and the Carpathian mountains.

Defense in Depth

Defense in Depth is a military strategy that entails building multiple layers of defence to protect a country’s vital assets and to slow or stop an enemy’s advance. The goal of this strategy is to make it as difficult for the enemy to breach the country’s defences as possible, as well as to force the enemy to fight on multiple fronts, which can weaken their resolve and deplete their resources.

One of the main advantages of the Defense in Depth strategy is that it allows a country to take advantage of its terrain and geographical features. A country with mountains, swamps, and rivers, for example, can create defensive barriers that can slow or stop the enemy’s advance. Furthermore, the Defense in Depth strategy allows a country to create multiple layers of defence by utilising its population and economic resources. A country with a large population, for example, can form a large number of militia units to fight guerrilla warfare.

Another feature of the Defense in Depth strategy is that it enables a country to fight a defensive war on its own terms. This means that the country can choose where and when to fight, as well as the type of warfare it employs. A country with the Defense in Depth strategy, for example, can choose to fight a guerrilla war, which is distinguished by hit-and-run tactics and the use of small, mobile units. This type of warfare can be extremely effective in containing a larger and better-equipped enemy force.

Furthermore, the Defense in Depth strategy is important in the psychological aspect of warfare. The enemy would have to fight in a foreign territory, far from home, and against a population that is motivated to defend their country. This can lead to a sense of isolation and despair among enemy soldiers, resulting in low morale and poor battlefield performance.

To generalise, the Defense in Depth strategy is a powerful military tactic that allows a country to take advantage of its terrain and population, perform a defensive war on its own terms, and build multiple layers of defence that can slow or stop the enemy’s advance. Furthermore, it contributes to the psychological aspect of warfare by instilling a sense of isolation and despair in enemy soldiers. Countries that use the Defense in Depth strategy are better able to defend themselves and eventually defeat the enemy.

Defense in Depth in Kyiv

The Kyiv region has flat terrain. A forested plains lies to the north, and a swamp rises along the Belarussian border. Furthermore, through artificial manipulations, the existing dam near Kyiv increases the volume of the swampy soil and allows it to grow in an even larger area. Chernobyl, with its existing Pripyat radioactive zone, adds another layer of protection. Against this backdrop, the Russian army was forced to launch an attack in the direction of Kyiv through marshy terrain, necessitating the use of road infrastructure. The aforementioned fact was especially true at the start of spring, when the snow began to melt in the environment and the so-called muddy season “Rasputitsa” began.

The first military engagement took place near Milove village on the border with Russia, in Luhansk Oblast. But as it soon appeared, the attack on Ukraine was not only from the east, but also from Belarus, directly directed at Kyiv. The main infantry and tank attacks were launched in four spearhead incursions, creating a northern front towards Kyiv, a southern front in Crimea, a south-eastern front at the cities of Luhansk and Donbas, and an eastern front. The Russian army tried to encircle the capital, Kyiv, but Ukrainian forces managed to hold ground and repel the attacks. The defense of Kyiv was led by General Oleksandr Syrskyi. Ukrainian forces utilized Western arms effectively, including the Javelin anti-tank missile and the Stinger anti-aircraft missile, thinning Russian supply lines and stalling the offensive.

Syrsky organized two rings of defense, one in the outer suburbs of the city and one within the capital, with the goal of protecting the downtown area and keeping the Russians fighting on the approaches to Kyiv. He also divided the city and surrounding region into sectors, assigned generals to lead each area, and created a clear chain of command for all Ukrainian military units and security services. A week before the invasion, the Ukrainian military moved all command posts closer to the probable axes of a Russian advance, and moved aviation assets off major bases. However, there was only one brigade of tanks available to defend the city, so training centers were ordered to create makeshift battalions and artillery systems were brought in. Ukrainian air defenses were moved the day before the invasion, allowing them to quickly counterattack. Over the next several days, Russian forces attempted to enter the city but were met with resistance, and their supply convoy from Belarus was halted.

During the first 24 hours of the invasion, most of the stationary air defense sites and military bases in Ukraine were targeted, as well as airfields and naval bases. Russian strikes were intensive but number of military defense platforms survived. The Russian attacks were focused on specific areas and the majority of the air defense coverage in the southern coast, like Kherson and Mykolaiv, was eliminated. A key aspect of the Russian strategy was to neutralize not just the leadership of the Ukrainian military but its main defense capabilities. But the Russian campaign revealed a lack of understanding of the mindset of the Ukrainian military by Russian special services. The motivation and preparation for the defense of the country turned out to be better than the Russians expected. Additionally, the Russian military had a weak approach to evaluating the success of their strikes, assuming that any action carried out was successful unless there was direct evidence to the contrary.

The Russians broke through the first line of Ukrainian defence near Ivankiv in 27th of February. Ukrainian forces destroyed the Teteriv River bridge at Ivankiv, halting the advance of Russian tanks towards Kyiv. The battle for Ivankiv did not prevent the Russian light units from moving directly in the direction of Kyiv. After the Russian landing forces were able to seize the Hostomel airport near Kyiv on February 24, Russian units tried to enter the settlement from the direction of Ivankiv, even though Ivankiv was not completely under their control yet. Russian tactics were aimed at reaching Kyiv as soon as possible. Ukrainians were able to stop the Russians in Bucha and Irpin. The explosions of the bridge on the Irpin River and the dam in the village of Dymer proved critical for the Russian army’s blocking manoeuvres. Russian supplies couldn’t move beyond the road because of the flooding, and Ukrainian artillery knew exactly where they were. At the very least, the Russians crossed the Irpin River near Moschun. The Russians began to deploy near Moschun on February 27. Despite the fact that Ukrainian artillery was heavily bombarding their military bridges, the Russians managed to enter the settlement on March 6. Kyiv’s Obolon district is located beyond Moschun.

Ukrainians were able to declare mobilisation, distribute weapons to volunteers in Kyiv, and successfully combat saboteurs during this time period, but fighting directly in a large urban centre was not desirable for Ukraine which can cause large scale of destruction and possible chaos in the capital.

The Russian attack near Moschun alongside Irpin river was halted due to the enemy’s long delay adjacent towns of Bucha, Irpin and Hostomel. The successful implementation of the mobilisation, the formation of territorial defence units, and the gathering of international volunteers is crucial to gain the upper hand during the defense tactics. The dam explosion in Dymer also caused problems for Russian units crossing the Irpin River. On March 21, the defence of Moschun became especially difficult, despite the massive use of anti-tank systems and artillery to halt the Russian army’s advance.

Another significant point was Makariv, which is located on the near of E-40 highway and is connected to Western Ukraine and Kyiv. The Russians intended to seize it, cut off its supply, and move towards Kyiv. The Ukrainians were successful, and after a fierce battle with Makariv, they pushed the Russians back towards the settlement’s entrance.

Mechanized military units had to move alongside infantry. Because the Russians were unable to take Chernihiv, they tried to bypass it and swiftly move to Kyiv by highway. The Ukrainians ambushed a Russian tank convoy in Brovary, northeast of Kyiv, leaving the Russians disorganized and forced to retreat after losing their tanks. One reason for this was the use of the main road, as well as the lack of auxiliary infantry units to protect tank units. Convoys of Russian supplies and equipment from the Sumy region to Kyiv encountered a similar situation. The ambushes resulted in the destruction of most of Russian convoys on this section. Logistical starvation hit the Russian army from all sides around Kyiv.

The Ukrainians successfully attempted to force the mass of Russian units into narrow stretches of terrain — impassable dirt roads, thawing fields or swamps that would lure vehicles and force them to consume more fuel. Fast-moving Ukrainian troops targeted vehicles that stayed on the main roads. Bridges and crossings had been mined and closed.

After exhausting the opponent, the Defense in Depth tactic includes preparation of launching a counterattack. When the Ukrainians had sufficiently weakened the Russian units in the vicinity of Kyiv and delivered some very accurate artillery strikes on Hostomel Airport, the Russian attack slowed and the Ukrainians shifted their focus to local counter-attacks and then to the liberation of settlements around Kyiv.

Mobilization of military forces and militia in large numbers slowed the Russian army’s speed and reduced its prior numerical superiority. The intensive activity of the Ukrainian artillery, as well as the effective use of Ukrainian and Western technology against armoured vehicles, resulted in bogging down in Russia’s both logistics and speed. Simultaneously, it became possible to supply Kyiv from Ukraine, which had not been affected by the Russian attack. This made the strategic depth effect a reality.

Against this backdrop, the Russian military forces preferred to leave the outskirts of the city.

On February 24, the Kremlin became engulfed in its own myth of invincibility. Expectations are set incorrectly when you only know what you want to hear. Because desired information does not always reflect reality, Sun Tzu’s formula about knowing one’s own and one’s opponent’s abilities is critical. Russian propaganda about its Kyiv’s weakness appears to be aimed not only at the West, but also at self-belief.

References:

Mykhaylo Zabrodskyi, Jack Watling, Oleksandr V Danylyuk and Nick Reynolds, ‘Preliminary Lessons in Conventional Warfighting from Russia’s Invasion of Ukraine: February–July 2022’, Special Resources, 30 November 2022, RUSI https://rusi.org/explore-our-research/publications/special-resources/preliminary-lessons-conventional-warfighting-russias-invasion-ukraine-february-july-2022

Sonne, P., Khurshudyan, I., Morgunov, S., & Khudov, K. (n.d.). Battle for Kyiv: Ukrainian valor, Russian blunders combined to save the capital. Washington Post. From https://www.washingtonpost.com/national-security/interactive/2022/kyiv-battle-ukraine-survival/

How Kyiv was saved by Ukrainian ingenuity as well as Russian blunders. (2022, April 10). Financial Times. From How Kyiv was saved by Ukrainian ingenuity as well as Russian blunders | Financial Times (ft.com)

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