Among Carl von Clausewitz’s many poignant dictums, the most commonly cited is undoubtedly that “war is not merely an act of policy but a true political instrument, a continuation of political intercourse, carried on by other means.” While Clausewitz never fought in a city like Fallujah, Kyiv, or Gaza if the Prussian general and philosopher of war could visit the battlefields of the twenty-first century, he would recognize modern urban warfare’s core challenges—and would find that his theories about war’s objective and the considerations needed for victory remain strikingly relevant.
Clausewitz wrote that “war is more than a true chameleon that slightly adapts its characteristics to the given case.” Its essential elements—violence, chance and probability, and subordination to policy—form what he famously described as a wunderliche Dreifaltigkeit, or “remarkable trinity.” Rather than being in conflict, these elements interact dynamically and, in successful systems like that of Napoleonic France, can operate in harmony. Clausewitz and his fellow Prussian reformers admired how the French system aligned popular will, military force, and political direction. Nowhere is the need for such harmony more acute than in modern urban warfare, where civilians, combatants, and national objectives share the same congested terrain. This environment tests the limits of military doctrine, challenges the notion of strategic clarity, and often leaves combatants with ambiguous definitions of victory.
In my work on urban warfare, from my book Understanding Urban Warfare to the numerous case studies I have authored and the field research I have conducted, I’ve seen the truths Clausewitz described play out on concrete streets and in bombed-out buildings. Urban warfare has become the norm, not the exception, and Clausewitz’s insights are not relics of Napoleonic Europe—they are essential tools for understanding the future of conflict.
Historical Context: Urban Warfare in Clausewitz’s Era
While Clausewitz never commanded modern urban battles, his military career immersed him in conflicts where cities played central strategic and symbolic roles. As a young officer in the Prussian Army, he fought in the Rhine campaigns (1793–1794), including the siege of Mainz, where revolutionary France defended the city against a Prussian-Austrian coalition. This early exposure to urban siege warfare—marked by fortified positions, complex logistics, and the suffering of civilians—gave Clausewitz firsthand insight into the unique challenges of fighting in and around cities.
Clausewitz’s later experiences reinforced the political and psychological weight of urban centers. As aide-de-camp to Prussian Prince Augustus Ferdinand, he was present during Napoleon’s 1806 victory in the battles of Jena and Auerstedt, which led to the French occupation of Berlin. He later served with the Russian Army during France’s 1812 invasion of Russia, taking part in the Battle of Borodino—a prelude to the burning of Moscow that serves as a powerful example of a capital’s strategic and symbolic significance. In 1815, having reentered Prussian service, he participated in the Battles of Ligny and Wavre, fighting on terrain where towns, roads, and rivers constrained operations and shaped outcomes.
Clausewitz drew clear conclusions from these experiences. In Principles of War, he argued that “public opinion is won through great victories and the occupation of the enemy’s capital.” He understood cities not only as symbolic centers of national will but also as logistical and operational hubs, writing of the importance of targeting “principal cities, storehouses, and large fortresses.” Though he did not witness the dense, protracted urban warfare of the modern era, Clausewitz’s strategic emphasis on cities foreshadowed many of the dynamics seen in today’s urban battles.
The Urban Trinity, Fog, and Friction: Clausewitz’s Theories in Concrete and Steel
Clausewitz’s “remarkable trinity”—violence and hatred (the people), chance and probability (in military action), and reason and policy (the government)—finds its most visceral expression in urban warfare. Cities collapse these elements into a single, compact battlespace. Unlike operations in open terrain, urban warfare places civilians, combatants, and political objectives in constant, physical contact. The Clausewitzian trinity becomes spatially literal: civilians live among the fight, military action is hyperlocalized and constrained, and every movement carries political weight.
Clausewitz also famously wrote, “No one starts a war—or rather, no one in his senses ought to do so—without first being clear in his mind what he intends to achieve by that war and how he intends to conduct it.” He noted, therefore, that “the first, the supreme, the most far-reaching act of judgment that the statesman and commander have to make is to establish . . . the kind of war on which they are embarking.”
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