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Clausewitz, Carl von


CLAUSEWITZ, CARL VON (1780–1831), Prussian general and theorist of war. Clausewitz's On War (1832) is the most celebrated study of its subject yet produced.

Carl von Clausewitz was born in Prussia in 1780 and entered the army at the age of twelve, on the eve of what would prove to be almost a quarter-century of conflict between the conservative monarchies of Europe and Revolutionary France. He first saw combat as an officer-cadet in the Rhineland campaign of 1793, an indecisive exercise in political maneuver typical of warfare under the Old Regime. He was also present thirteen years later, in October 1806, when Napoleon I (r. 1804–1814/15) crushed the Prussian army at the twin battles of Jena and Auerstädt, a defeat that exemplified the contrast between the cautious principles of the past and the new military dynamism the French Revolution had unleashed. Prussia's subsequent decision to align itself with its conqueror left Clausewitz embittered, and in 1812 he resigned his commission to serve in Russia. There he witnessed at firsthand the epic struggle by which Napoleon's grip on Europe was broken. As war moved back into Germany, Clausewitz helped organize irregular forces against the French. The Waterloo campaign (1815) found him once again in a Prussian uniform, as chief of staff to a corps.

Clausewitz's work as a historian and theorist of war rested upon these experiences, without being limited by them. Most interpreters of Napoleonic warfare were inclined to see it as the epitome of the military art, in which principles and practices dimly anticipated in earlier times had at last been fully realized. Clausewitz, on the other hand, recognized that Napoleon's achievements were historically contingent, arising from social and technological circumstances that were bound to change. It was thus wrong to imagine that any temporarily ascendant set of military methods could possess permanent validity. For Clausewitz, the goal of theory was not to codify the best practices of a given moment, but to grasp the essence of war as a whole. It is for this reason that his ideas have continued to afford insight, long after the historical conditions that inspired them have faded into the past.

Clausewitz's work stands at some distance from the mainstream of military thought in the early nineteenth century, which was overwhelmingly concerned with the spatial and temporal relationships of armies as they maneuvered against each other. Clausewitz recognized that such relationships might be highly significant. But he was equally concerned with other, less tangible factors that also shaped the outcome whenever such forces actually met. Foremost among these were the political goals that brought the combatants within weapons' range of each other in the first place. Armed forces were the creatures of political communities. War was therefore a political instrument, which could never be understood exclusively in its own terms. Political interests defined military objectives, and often set limits on the scale of violence that a belligerent was prepared to employ to achieve its ends. At the same time, the emotions violence incited might challenge and even alter the aims of policy, setting in motion an escalatory spiral that knew no natural limit. Thus politics calls forth the violence of war, shapes its character, and determines its scope; but it may also become subject to war's passion and destructiveness, bending in turn to accommodate its unique demands.

Few students of war have ever been as sensitive to its psychological dimensions. The political purposes of belligerent communities, the raw contest of wills that motivates violent struggle, the talent and insight of commanders, the morale of troops, the loyalty of the citizen—these are the essential building blocks from which Clausewitz's vision of war was constructed. Regardless of the form it might take, war was always an environment dominated by chance, and made unique cognitive and moral demands on those caught up in it. For Clausewitz, the fear and confusion that pervade war were not exogenous variables, but fundamental realities that underlay that most universal of military experiences: the tendency of things to go terribly wrong, which he characterized as "friction." Friction in turn found its natural complement in the concept of "genius," by which Clausewitz meant those ineluctable qualities of character and intellect that made a successful commander. It was the will and intelligence of the commander that drove the machinery of war forward—but always at the risk of wearing it out completely.

Clausewitz was intensely interested in these sorts of complex, ambiguous interactions. He habitually analyzed important concepts in terms of creative tension, by which opposing ideas or countervailing forces are seen to define each other. Risk and reward, attack and defense, friction and genius, strategy and politics, reason and chance, victory and defeat—these and other mutually dependent concepts weave their way recursively throughout his work, and provide its distinctive texture. On War lacks the categorical judgments and didactic purpose that are characteristic of modern strategic theory. Its aim was not to teach people how to fight, but rather to show them how to think about war. It has always been regarded as a formidable text, and its initial public reception, while respectful, was decidedly limited: the first edition of fifteen hundred copies appeared posthumously following Clausewitz's death from cholera in 1831, and it was still in print twenty years later.

His ascendancy as the preeminent theorist of modern war dates from the latter decades of the nineteenth century, when, in the wake of Prussia's victories over Austria and France (1866–1871), the military architect of those triumphs, Count Helmuth Karl Bernhard von Moltke (1800–1891), drew attention to Clausewitz's work. One must be cautious about assigning direct influence to any work of scholarship. Many of the ideas that future generations would come to consider "Clausewitzian"—an emphasis upon decisive battle, concentration of effort, tactical agility, and the overriding importance of moral forces—were commonplaces among intelligent soldiers of post-Napoleonic Europe, to which Clausewitz's work may, at most, have lent some additional intellectual authority. In general, the appeal of Clausewitz for professional soldiers has resided primarily in his emphasis upon the central virtues of initiative, aggressiveness, mental flexibility, and self-reliance at all levels of command. These ideas comported well with the decentralized command systems that would be required to wage war in the industrial era. At the same time, the mechanization of war strengthened the technocratic and managerial ethos of military officers, and with it their natural resistance of Clausewitz's most distinctive claim: that war is permeated by politics not just in its origins and outcome, but at every level of its conduct. Even among soldiers who accept their subordination to civilian authority as a constitutional principle, the introduction of political considerations into the conduct of military operations is still widely regarded as interference in an activity best left to professional experts.

See alsoArmies; French Revolutionary Wars and Napoleonic Wars; Military Tactics; Napoleon.


Aron, Raymond. Clausewitz: Philosopher of War. London, 1983.

Clausewitz, Carl von. On War. Edited and translated by Michael Howard and Peter Paret. Princeton, N.J., 1976.

——. Historical and Political Writings. Edited and translated by Peter Paret and Daniel Moran. Princeton, N.J., 1992.

Paret, Peter. Clausewitz and the State. Oxford, U.K., 1976.

Daniel Moran

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