Clausewitz's Christian name is sometimes given in non-German sources as Carl Philipp Gottlieb, Carl Maria, or misspelled Karl due to reliance on mistaken source material, conflations with his wife's name, Marie, or mistaken assumptions about German orthography. Carl Philipp Gottfried appears on Clausewitz's tombstone and is thus most likely to be the correct version. The tombstone reads:

Hier ruht in Gott

Carl Philipp Gottfried von Clausewitz

koenigl. General-Major u. Inspecteur der Artillerie

geboren 1 Juni 1780

gestorben 16 Nov 1831

Here rests with God

Carl Philipp Gottfried von Clausewitz

In the royal service, Major General and Inspector of the Artillery

Born June 1, 1780

Died November 16, 1831

Clausewitz was born on June 1, 1780 in Burg bei Magdeburg, Kingdom of Prussia, the fourth and youngest son of a lower middle-class family. His grandfather, the son of a Lutheran pastor, had been a professor of theology. Clausewitz's father was once a lieutenant in the Prussian army and held a minor post in the Prussian internal revenue service. Clausewitz entered the Prussian military service at the age of twelve as a Lance-Corporal, eventually attaining the rank of Major-General.

Clausewitz served in the Rhine Campaign (1793—1794) e.g. the Siege of Mainz, when the Prussian army invaded France during the French Revolution, and later served in the Napoleonic Wars from 1806 to 1815. Clausewitz entered the Kriegsakademie in Berlin (also cited variously as "The German War School," the "Military Academy in Berlin," and the "Prussian Military Academy") in 1801 (age 21 years), studied the writings of the philosopher Immanuel Kant, and won the regard of General Gerhard von Scharnhorst, the future first chief of staff of the new Prussian Army (appointed 1809). Clausewitz, along with Hermann von Boyen (1771–1848) and Karl von Grolman (1777–1843), were Scharnhorst's primary allies in his efforts to reform the Prussian army between 1807 and 1814.

Clausewitz served during the Jena Campaign as aide-de-camp to Prince August. At the Battle of Jena-Auerstedt on October 14, 1806 – when Napoleon invaded Prussia and defeated the massed Prussian-Saxon army commanded by Karl Wilhelm Ferdinand, Duke of Brunswick – he was captured, one of the 25,000 prisoners captured that day as the Prussian army disintegrated. He was twenty-six at the time.

Clausewitz was held prisoner in France from 1807 to 1808. Returning to Prussia, he assisted in the reform of the Prussian army and state. He also married the socially prominent Countess Marie von Brühl and socialized with Berlin's literary and intellectual elite. Opposed to Prussia's enforced alliance to Napoleon, he left the Prussian army and subsequently served in the Russian army from 1812 to 1813 during the Russian Campaign including at the Battle of Borodino. Like many Prussian officers living in Russia, he joined the Russian-German Legion in 1813. In the service of the Russian Empire, Clausewitz helped negotiate the Convention of Tauroggen (1812), which prepared the way for the coalition of Prussia, Russia, and the United Kingdom that ultimately defeated Napoleon I and his allies.

In 1815, the Russo-German Legion was integrated into the Prussian Army and Clausewitz re-entered Prussian service. He was soon appointed chief of staff to Johann von Thielmann's III Corps. In that capacity, he served at the Battle of Ligny and the Battle of Wavre during the Waterloo Campaign in 1815. The Prussians were defeated at Ligny – south of Mont-Saint-Jean and the village of Waterloo – by an army led personally by Napoleon, but Napoleon's failure to actually destroy the Prussian forces led to his eventual defeat a few days later at the Battle of Waterloo, when the Prussian forces arrived on his right flank late in the afternoon and joined the Anglo-Dutch forces pressing Napoleon's front.

Clausewitz was promoted to Major-General in 1818 and appointed director of the Kriegsakademie, where he served until 1830. In the latter year, the outbreak of several revolutions around Europe and a crisis in Poland appeared to presage another major European war. Clausewitz was appointed chief-of-staff to the only army Prussia was able to mobilize, which was sent to the Polish border. He subsequently died in a cholera outbreak in 1831. His widow was left to publish his magnum opus on the philosophy of war posthumously, in 1832 – a book he had started working on in 1816 but had not completed.

Although Clausewitz participated in numerous military campaigns, he was primarily a military theorist interested in the examination of war. He wrote a careful, systematic, philosophical examination of war in all its aspects, as he saw it and taught it. The result was his principal work, On War, the West's premier work on the philosophy of war. His examination was so carefully considered that it was only partially completed by the time of his death. Clausewitz sought to revise the text, in 1827 and just before his death, to include more material on counter-insurgency and forms of war other than between states, but these revisions were never included in the published document. Other soldiers before this time had written treatises on various military subjects, but none undertook a great philosophical examination of war on the scale of Clausewitz's and Tolstoy's, both of which were inspired by the events of the Napoleonic Era.

Clausewitz's work is still studied today, demonstrating its continued relevance. Lynn Montross writing on that topic in War Through the Ages said; "This outcome...may be explained by the fact that Jomini produced a system of war, Clausewitz a philosophy. The one has been outdated by new weapons, the other still influences the strategy behind those weapons."

Clausewitz introduced systematic philosophical contemplation into Western military thinking, with powerful implications not only for historical and analytical writing but for practical policy, military instruction, and operational planning. He relied on his own experiences, contemporary writings about Napoleon, and on a small body of historical sources. His historiographical approach is evident in his first extended study, written when he was twenty-five, of the Thirty Years War. He rejects the Enlightenment's view of the war as a chaotic muddle and instead explains its drawn-out operations by the economy and technology of the age, the social characteristics of the troops, and the commanders' politics and psychology. From then on, his attention to psychological factors added to the compound character of his interpretations. In On War, Clausewitz sees all wars as the sum of decisions, actions, and reactions in an uncertain, dangerous context but also as a socio-political phenomenon. He has several definitions, the most famous one being that war is the continuation of politics by other means. He also stressed the complex nature of war which encompasses both the socio-political and the operational and stresses the primacy of national policy.

Clausewitz conceived of war as a political, social, economic and military totality involving the entire population of a nation at war. He saw war as a social act and as an extension of politics. Unlike Jomini, who stressed control of central geographical locations, he stressed that wars are decided by decisive battles.

Clausewitz's emphasis on the superiority of the defense suggests aggressive attacks can be failures. He emphasizes the fusion of the regular army with militia, or citizen soldiers, as the only effective method of national defense. This point is especially important as it ends the independence and isolation of the regular military and democraticizes the armed forces much as universal suffrage democraticized politics.

In contrast to Jomini, Clausewitz largely dismissed the value of military intelligence: "Many intelligence reports in war are contradictory; even more are false, and most are uncertain. ... In short, most intelligence is false." His conclusions were influenced by his personal experiences in the Prussian Army, which was often in an intelligence fog due to the superior abilities of Napoleon's system. Clausewitz acknowledges that friction creates enormous difficulties for the realization of any plan, and the "fog of war" hinders commanders from knowing what is happening, but it is precisely in respect of this challenge that he develops the concept of military genius, whose capabilities are seen above all as the executive arm of planning.

Principal ideas

Some of the key ideas discussed in On War include:

• the dialectical approach to military analysis
• the methods of "critical analysis"
• the nature of the balance-of-power mechanism
• the relationship between political objectives and military objectives in war
• the asymmetrical relationship between attack and defense
• the nature of "military genius" (involving matters of personality and character, beyond intellect)
• the "fascinating trinity" (wunderliche Dreifaltigkeit) of war
• philosophical distinctions between "absolute" or "ideal war," and "real war"
• in "real war," the distinctive poles of a) limited war and b) war to "render the enemy helpless"
• "war" belongs fundamentally to the social realm...rather than to the realms of art or science
• "strategy" belongs primarily to the realm of art
• "tactics" belongs primarily to the realm of science
• the importance of "moral forces" (more than simply "morale") as opposed to quantifiable physical elements
• the "military virtues" of professional armies (which do not necessarily trump the rather different virtues of other kinds of fighting forces)
• conversely, the very real effects of a superiority in numbers and "mass"
• the essential unpredictability of war
• the "fog" of war
• "friction"
• strategic and operational "centers of gravity"
• the "culminating point of the offensive"
• the "culminating point of victory"

Clausewitz used a dialectical method to construct his argument, leading to frequent misinterpretation of his ideas. British military theorist B. H. Liddell Hart contends that the enthusiastic acceptance of the Prussian military establishment – especially Moltke the Elder – of what they believed to be Clausewitz's ideas, and the subsequent widespread adoption of the Prussian military system worldwide, had a deleterious effect on military theory and practice, due to their egregious misinterpretation of his ideas:

As so often happens, Clausewitz's disciples carried his teaching to an extreme which their master had not intended. ... [Clauswitz's] theory of war was expounded in a way too abstract and involved for ordinary soldier-minds, essentially concrete, to follow the course of his argument – which often turned back from the direction in which it was apparently leading. Impressed yet befogged, they grasped at his vivid leading phrases, seeing only their surface meaning, and missing the deeper current of his thought.

As described by Christopher Bassford, professor of strategy at the National War College of the United States:

One of the main sources of confusion about Clausewitz's approach lies in his dialectical method of presentation. For example, Clausewitz's famous line that "War is a mere continuation of politics by other means," ("Der Krieg ist eine bloße Fortsetzung der Politik mit anderen Mitteln") while accurate as far as it goes, was not intended as a statement of fact. It is the antithesis in a dialectical argument whose thesis is the point – made earlier in the analysis – that "war is nothing but a duel [or wrestling match, a better translation of the German Zweikampf] on a larger scale." His synthesis, which resolves the deficiencies of these two bold statements, says that war is neither "nothing but" an act of brute force nor "merely" a rational act of politics or policy. This synthesis lies in his "fascinating trinity" [wunderliche Dreifaltigkeit]: a dynamic, inherently unstable interaction of the forces of violent emotion, chance, and rational calculation.

Another example of this confusion is the idea that Clausewitz was a proponent of total war as used in the Third Reich's propaganda in the 1940s. He did not coin the phrase as an ideological ideal – indeed, Clausewitz did not use the term "total war" at all. Rather, he discussed "absolute war" or "ideal war" as the purely logical result of the forces underlying a "pure," Platonic "ideal" of war. In what Clausewitz called a "logical fantasy," war cannot be waged in a limited way: the rules of competition will force participants to use all means at their disposal to achieve victory. But in the real world, such rigid logic is unrealistic and dangerous. As a practical matter, the military objectives in real war that support one's political objectives generally fall into two broad types: "war to achieve limited aims" and war to "disarm" the enemy, that is, "to render [him] politically helpless or militarily impotent." Thus the complete defeat of one's enemies may be neither necessary, desirable, nor even possible.

In modern times the reconstruction of Clausewitzian theory has been a matter of some dispute. One prominent analysis was that of Panagiotis Kondylis, a Greek-German writer and philosopher who opposed the interpretations of Raymond Aron, in Penser la Guerre, Clausewitz, and other liberal writers. According to Aron, Clausewitz was one of the very first writers to condemn the militarism of the Prussian general staff and its war-proneness, based on Clausewitz's argument that "war is a continuation of politics by other means". In Theory of War Kondylis claims that this is inconsistent with Clausewitzian thought. He claims that Clausewitz was morally indifferent to war and that his advice regarding politics' dominance over the conduct of war has nothing to do with pacifistic ideas. For Clausewitz, war is simply a means to the eternal quest for power, of raison d'État in an anarchic and unsafe world.

Other notable writers who have studied Clausewitz's texts and translated them into English are the war specialists Peter Paret of Princeton University and Sir Michael Howard, and the philosopher, musician, and game theorist Anatol Rapoport. Howard edited the widely used Penguin edition of On War and has produced comparative studies of Clausewitz and other theorists, such as Tolstoy. Bernard Brodie's A Guide to the Reading of "On War", in the 1976 Princeton translation, expressed his own interpretations of the Prussian's theories and provided students with an influential synopsis of this vital work.

Despite his death just prior to completing On War, Clausewitz' ideas have been widely influential in military theory and a strong influence on German military thought. Later Prussian and German generals such as Helmuth Graf von Moltke were clearly influenced by Clausewitz: Moltke's notable statement that "No campaign plan survives first contact with the enemy" is a classic reflection of Clausewitz's insistence on the roles of chance, friction, "fog," and uncertainty in war.

After 1890, Clausewitz's influence spread to British thinking as well, as typified by naval historian Julian Corbett (1854-1922). Clausewitz had little influence on American military thought before 1945, but influenced Lenin and the Soviet tradition, as Lenin emphasized the inevitability of wars among capitalist states in the age of imperialism and presented the armed struggle of the working class as the only path toward the eventual elimination of war. Clausewitz directly influenced Chinese leader Mao Zedong, who read On War in 1938 and organized a seminar on Clausewitz as part of the educational program for the Party leadership in Yan'an. Thus the "Clausewitzian" content in many of Mao's writings is not merely second-hand knowledge, via Lenin (as many have supposed), but reflects Mao's own in-depth study.

The idea that war involves inherent "friction" which distorts, to a greater or lesser degree, all prior arrangements, has become common currency in other fields as well, such as business strategy and sports. The phrase fog of war derives from Clausewitz's stress on how confused warfare can seem while one is immersed within it. The term center of gravity, used in a specifically military context, derives from Clausewitz's usage, which he took from Newtonian Mechanics. In US military doctrine, "center of gravity" refers to the basis of an opponent's power, at either the operational, strategic, or political level.

Late 20th and early 21st century

After 1970, some theorists claimed that nuclear proliferation made Clausewitzian concepts obsolete after a period – the 20th century – in which they dominated the world. John E. Sheppard, Jr., argues that by developing nuclear weapons, state-based conventional armies simultaneously both perfected their original purpose – to destroy a mirror image of themselves – and made themselves obsolete. No two nuclear powers have ever used their nuclear weapons against each other, instead using conventional means or proxy wars to settle disputes. If, hypothetically, such a conflict did in fact occur, presumably both combatants would be effectively annihilated.

The end of the 20th century and the beginning of the 21st century has seen many instances of state armies attempting to suppress insurgencies, terrorism, and other forms of asymmetrical warfare. Because Clausewitz focused solely on wars between countries with well-defined armies, many commentators have argued that On War has lost its analytical edge as a tool for understanding war as it is currently fought. Some have gone further, and suggested that Clausewitz's best known aphorism, that war is a continuation of policy by other means, is not only irrelevant today but also inapplicable historically. Others, however, argue that the essentials of Clausewitz's theoretical approach remain valid, but that our thinking must adjust to changed realities. Knowing that "war is an expression of politics by other means" does us no good unless we use a definition of "politics" which is appropriate to the circumstance and to the cultural proclivities of the combatants in each specific situation; this is especially true when warfare is carried on across a cultural or civilizational divide, and the antagonists do not share as much common background as did many of the participants in the First and Second World Wars.

Literature

• 1945: In the Horatio Hornblower novel The Commodore, by C. S. Forester, the protagonist meets von Clausewitz during the events surrounding the defence of Riga.
• 1945: In That Hideous Strength by C. S. Lewis, Lord Feverstone (Dick Devine) defends rudely cutting off another professor by saying "[...] but then I take the Clauswitz view. Total war is the most humane in the long run."
• 1955: In Ian Fleming's novel Moonraker, James Bond reflects that he has achieved Clausewitz's first principle in securing his base, though this base is a relationship for intelligence purposes and not a military installation.
• 2000: In the Ethan Stark military science fiction book series by John G. Hemry, Clausewitz is often quoted by Private Mendoza and his father Lieutenant Mendoza to explain events that unfold during the series.
• 2004: Bob Dylan mentions Clausewitz on pages 41 and 45 of his Volume One, saying he had "a morbid fascination with this stuff," that "Clausewitz in some ways is a prophet" and reading Clausewitz can make you "take your own thoughts a little less seriously." Dylan says that Vom Kriege was one of the books he looked through among those he found in his friend's personal library as a young man playing at The Gaslight Cafe in Greenwich Village.

Film

• 1962: In the film Lawrence of Arabia, General Allenby (Jack Hawkins) contends to T. E. Lawrence (Peter O'Toole) that "I fight like Clausewitz, you fight like Saxe." To which Lawrence replies, "We should do very well indeed, shouldn't we?"
• 1977: In Sam Peckinpah's film Cross of Iron, Feldwebel Steiner (James Coburn) has an ironic conversation in the trenches between hostilities with the advancing Red Army with his comrade, Cpl. Schnurrbart, in which they refer to German philosophers and their views on war. Cpl. Schnurrbart: " ...and von Clausewitz said, 'war is a continuation of state policy by other means.'" "Yes," Steiner says, overlooking the trenches, " ...by other means."
• 1995: In the film Crimson Tide, the naval officers of the nuclear submarine have a discussion about the meaning of the quote "War is a continuation of politics by other means." The executive officer (Denzel Washington) contends that the interpretation of Clausewitz's ideas by the captain (Gene Hackman) is too simplistic.
• 2007: In the film Lions for Lambs, during a military briefing in Afghanistan Lt. Col. Falco (Peter Berg) says: "Remember your von Clausewitz: 'Never engage the same enemy for too long or he will ...'", "adapt to your tactics", completes another soldier.
• 2009: In the film Law Abiding Citizen, Clausewitz is frequently quoted by Clyde Shelton, the main character played by Gerard Butler.

Notes

Bibliography

Primary sources

• Clausewitz, Carl von. Historical and Political Writings, ed. Peter Paret and Daniel Moran (1992).
• Clausewitz, Carl von. Col. J. J. Graham, translator. Vom Kriege. On War — Volume 1, Project Gutenberg eBook.

Secondary sources

• Aron, Raymond. Clausewitz: Philosopher of War. (1985). 418 pp.
• Bassford, Christopher. Clausewitz in English: The Reception of Clausewitz in Britain and America, 1815-1945. New York: Oxford University Press, 1994. Full text on-line here.
• Echevarria, Antulio J., II. After Clausewitz: German Military Thinkers before the Great War. (2001). 346 pp.
• Echevarria, Antulio J., II. Clausewitz and Contemporary War (2007) excerpt and text search
• Gat, Azar. The Origins of Military Thought from the Enlightenment to Clausewitz (1989)
• Handel, Michael I., ed. Clausewitz and Modern Strategy. 1986. 324 pp.
• Handel, Michael I. Masters of War: Classical Strategic Thought. (2001) 482 pages. Based on comparison of Clausewitz's On War with Sun Tzu's The Art of War
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• Liddell Hart, B. H. Strategy London:Faber, 1967. Second rev. ed.
• Muhm, Gerhard. German Tactics in the Italian Campaign , http://www.larchivio.org/xoom/gerhardmuhm2.htm
• Paret, Peter. Clausewitz and the State: The Man, His Theories, and His Times. Princeton: Princeton University Press, 1976.
• Paret, Peter. "From Ideal to Ambiguity: Johannes von Müller, Clausewitz, and the People in Arms." Journal of the History of Ideas 2004 65(1): 101-111. Issn: 0022-5037 Fulltext: Project Muse
• Rogers, Clifford J. "Clausewitz, Genius, and the Rules", The Journal of Military History, Vol. 66, No. 4. (2002), pp. 1167—1176.
• Rothfels, Hans “Clausewitz” pages 93—113 from The Makers of Modern Strategy edited by Edward Mead Earle, Gordon A. Craig & Felix Gilbert, Princeton, N.J.: Princeton University Press, 1943.
• Smith, Hugh. On Clausewitz: A Study of Military and Political Ideas. (2005). 303 pp.
• Strachan, Hew, and Andreas Herberg-Rothe, eds. Clausewitz in the Twenty-First Century (2007) excerpt and text search
• Sumida, Jon Tetsuro. "On the Relationship of History and Theory in on War: the Clausewitzian Ideal and its Implications." Journal of Military History 2001 65(2): 333-354. Issn: 0899-3718 in Jstor
• Villacres, Edward J. and Bassford, Christopher. "Reclaiming the Clausewitzian Trinity". Parameters, Autumn 95, pp. 9—19,
• Wallach, Jehuda L. The Dogma of the Battle of Annihilation: The Theories of Clausewitz and Schlieffen and Their Impact on the German Conduct of Two World Wars. (1986). 334 pp.