This week marks one year since Russia’s invasion of Ukraine kicked off a war that has offered up a wide range of lessons on the conduct of large-scale combat operations in the twenty-first century. In those twelve months, the war has touched all corners of Ukraine and yet its most defining features have been fights for control of cities. But while urban areas may be the war’s most important environment, at least to this point, no two urban battles have been the same. The battles in Kyiv, Mariupol, and Kherson, and the ongoing battle in Bakhmut have taken very different forms. This fact offers a valuable opportunity: by searching for elements common to each of these battles, despite the different contexts in which they occurred, we can illuminate fundamental lessons on urban warfare.

Four particular lessons stand out. Most of them are not new. Rather, they have been on display in previous wars, but too often ignored or forgotten. This is a mistake we should not make again. The US military must learn from the current war in Ukraine to avoid paying the penalty, in blood and treasure, when it finds itself in its own urban battles in the future.

1. In war, cities are important—even the ones with no military value.

Russia’s war in Ukraine demonstrates that cities often present strategic, operational, and tactical objectives in major land wars. Since the start of this war, urban areas have been the focal points—the places where much of the most intense fighting has occurred. When asked to identify one of the war’s major battles, most observers are likely to name one of the urban fights listed above—Kyiv, Mariupol, or Kherson. Others who have watched the conflict especially closely may even name Severodonetsk or Lysychansk, which Russia seized earlier in the war. In fact, most would be hard-pressed to name a major battle that did not occur in, or for, a city. Neither side has been able to avoid or bypass urban areas because they are tactically, operationally, and sometimes strategically important.

Kyiv, for example, is the most strategically important terrain in the country. As the capital city, it houses Ukraine’s national government, giving it obvious political significance. Ukraine successfully defended its capital in the opening month of the war and achieved its vital goal: survival of the nation and its government. Russia, by contrast, failed to achieve its strategic goal: the rapid overthrow the Ukrainian government and the installation of a Russian proxy in its place.

Kherson is an operationally important city (and arguably a strategically significant one, as well). It is a critical Black Sea port and a gateway to Crimea. Controlling this provincial capital means controlling Ukraine’s south. Russia seized the city in the opening days of the war but was forced to withdraw in October. By liberating Kherson city, Ukraine prevented Russia from achieving its stated strategic objective of annexing the entire Kherson region as Russian territory.

Yet not all cities are strategically or operationally significant; many, in fact, do not even offer much tactical value from a strictly military perspective. Cities such as Severodonetsk, which Russia seized in June, and Bakhmut, where the fighting continues today, represent little military value on their own. Controlling them does not offer either side a marked military advantage. Yet the fighting for both was—and in the case of Bakhmut, remains—extremely intense.

Why are the militaries of each nation fighting so hard for seemingly insignificant terrain? It is because they are symbolically important, and their control consequently has political value. Ukraine does not want a city of seventy thousand (Bakhmut) or one hundred thousand (Severodonetsk) to fall into Russian hands. Likewise, Russia wants to seize these cities to demonstrate progress in a war that has not gone well. Seizing thousands of rural square miles in the Zaporizhzhia region simply does not have the same political effect. Because war is inherently political, these seemingly insignificant pieces of terrain become tactically and operationally important and yet another reason why fighting in urban areas cannot be avoided.

2. The foundational task of urban warfare is not clearing.

The many urban battles of Ukraine consistently show that the foundational task of high-intensity warfare against a peer enemy in dense urban terrain is not clearing—not clearing rooms, not clearing buildings, and not clearing cities. While very limited methodical clearing operations have been observed, conducting them has not been the dominant requirement for either side.

The more crucial tasks in these battles were placing either the defender or attacker at a disadvantage through fire and maneuver: finding, fixing, and destroying a hidden or embedded enemy; holding or seizing key urban terrain features such as strongpoints, bridge and river crossing, streets, and high ground; or, as was the case for Ukrainian forces in Kherson, placing the adversary in such an untenable position that they were forced to flee the city without even attempting to defend it.

During the Battle of Kyiv, Ukrainian defenders, both military and civilian, emplaced barriers, flooded rivers, and employed other techniques to canalize mounted Russian formations into narrow, dense urban avenues of approach where they were ambushed and defeated in detail. In the battles of Severodonetsk and Kherson, whichever side controlled or influenced the river crossings—something present in most major cities—had the advantage by cutting off one side of the river from resupply or reinforcements.

The vital task of modern urban warfare is the ability to combine arms—fires (rocket, artillery, and mortars), armor, infantry, engineers, aerial strike and reconnaissance platforms, as well as cyber, space, and other capabilities—at a precise time and location to achieve key tasks like identifying and destroying enemy personnel or their critical capabilities to hold or attack urban terrain. A military force, like Russia, that attempts to deploy individual arms independently and without mutual support—first artillery, then armor, followed by infantry, for instance—will continue to pay extremely high costs in casualties and will fail to achieve its military mission in urban terrain.

3. In cities, armies must be able to defend and attack—and switch between the two rapidly.

As this war has shown, cities cannot be bypassed. As such, one side must defend and the other attack. But wars and battles are fluid, so militaries must be capable of doing both and of moving between offense and defense seamlessly and quickly. In the opening days of the war, the Ukrainians were largely defending and the Russians attacking. But even on the war’s very first day, Ukraine conducted at least one counterattack against which the Russians defended poorly: the battle of Hostomel Airport. It is but one example that demonstrates how militaries must be capable of not just defending and attacking in urban terrain, but also switching between the two more quickly than the adversary.

In the opening hours of the war, Russia sent at least thirty helicopters carrying up to three hundred Russian airborne soldiers to seize the airport, located on the outskirts of Kyiv, and establish an airbridge to support the assault on the capital. Within hours, the Russian forces’ attack had secured the airport—but they failed to defend it. That evening, a force consisting of Ukraine’s 4th Rapid Reaction Brigade and other units counterattacked and seized the airfield because the Russian airborne troops had failed to establish an effective defense and lacked the capabilities necessary to hold it. Ukrainian forces recognized that they were in an untenable position and withdrew that same night, but the damage they sought to inflict had been done. They had cratered the runway, thwarting Russia’s plan to use it as a key bridge to rapidly bring in the forces needed to take the city.

In September, Ukrainian forces liberated the towns of Izyum and Kupiansk, both of which had been captured during the war’s first two months. These urban areas were key to Russian forces in the region because they were both vital logistical hubs, as urban areas often are because they sit along transportation and rail lines that military forces need to resupply forward troops and project power. Russia had fought a bitter battle to seize Izyum, and like the Hostomel Airport, failed to defend it.

At the battle of Mariupol, just a few thousand Ukrainian defenders held the city, which had a prewar population of five hundred thousand, for over eighty days against a Russian force five to eight times larger. The Ukrainians varied their defenses and how they used the complex, dense urban terrain to hold off the larger force. They leveraged the city’s heavy-clad, industrial buildings and its subterranean network very effectively. The tactical battle for Mariupol had important operational impacts: by holding out as long as they did, Ukrainian defenders prevented up to forty thousand Russian forces from fighting on other fronts where they may have shifted the tide of the war.

4. An army that cannot execute combined arms maneuver will suffer.

This war is being fought by two very different militaries using very different strategies. After committing itself to a massive reform in 2016, Ukraine’s military entered the war very different from the one Russia and Russian-led separatists had faced in 2014–15. Ukraine’s military had the doctrine, leadership, training, culture, and morale necessary to effectively employ combined arms maneuver at scale. While combined arms maneuver is important for any environment, it is especially important in cities.

Urban warfare is the ultimate test of combined arms maneuver. The side that can better integrate fires, armor, infantry, engineers, and intelligence has an advantage. The history of urban warfare consistently proves this to be a fundamental reality. Over twelve months of war, Ukrainian forces have simply been better at conducting combined arms maneuver than their Russian counterparts.

Russia’s military, by contrast, underwent its own reforms over the past decade, but has proven itself to be poorly led, poorly trained, poorly motivated, even lacking adequate arms like infantry in its base formations. Unsurprisingly, as a result, Russian forces have often proven themselves incapable of executing complex maneuvers on the battlefield. Lacking the ability to effectively employ combined arms maneuver, Russia’s primary method to attack cities is to leverage its one advantage: mass.

In Mariupol, Severodonetsk, Bakhmut, and other cities, Russia’s approach has been a crude one: conduct large artillery barrages and throw thousands of soldiers into the city to dislodge a much smaller Ukrainian force. At times, this has been effective—but even these successes have come at a great cost, forcing Russia to tie up manpower, accept large numbers of casualties, and expend huge numbers of munitions for only incremental territorial gains of seemingly little military value. Given the sheer size of Russia’s military, it is safe to say that if Russia was employing effective combined arms maneuver in Ukraine’s cities, it would be having much greater success.

Ukraine is a vast country of almost a quarter of a million square miles. And yet it is the small percentage of Ukrainian territory covered by cities that has disproportionately characterized the conduct of the war over the past year. For those searching for lessons on the future of warfare, this fact is telling. The lessons offered up by the past twelve months of the war in Ukraine must be identified, and they must inform the ways the US military conceives of, plans and prepares for, and conducts urban warfare.

John Spencer is chair of urban warfare studies at the Modern War Institute, codirector ofMWI’s Urban Warfare Project, and host of the Urban Warfare Project Podcast. He served twenty-five years as an infantry soldier, which included two combat tours in Iraq. In June 2022, he and Liam Collins traveled independently to Ukraine to research the defense of Kyiv. He is the author of the book Connected Soldiers: Life, Leadership, and Social Connection in Modern War and coauthor of Understanding Urban Warfare.

Liam Collins, PhD was the founding director of the Modern War Institute at West Point and served as a defense advisor to Ukraine from 2016 to 2018. He is a retired Special Forces colonel with deployments to Iraq, Afghanistan, Bosnia, the Horn of Africa, and South America. He is coauthor of the book Understanding Urban Warfare.

The views expressed are those of the authors and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.