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Book Review Essays

Carl von Clausewitz by Franz Michelis

Bildarchiv Preussischer Kulturbesitz/Art Resource 346330

Carl von Clausewitz, lithograph by Franz Michelis after a lost painting by Karl Wilhem Wach.

Clausewitz and On War

by Bill Bentley

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“ ...like a beam of light from the past ...”

General Colin Powell first encountered Carl von Clausewitz’s treatise, On War, in 1975 when he attended War College. According to Powell: “It was like a beam of light from the past, still illuminating present day military quandaries.”1 More recently, another distinguished military officer, General Sir Rupert Smith, cited Clausewitz no less than 10 times in his influential book, The Utility of Force.

The list of testimonials to von Clausewitz’s magisterial On War is a long one indeed. General Helmut von Moltke once remarked that the only books of interest for him were Homer’s Iliad, the Bible, and On War. In the inter-war period (1918-1939), two British colonels added their endorsement of Clausewitz. J.F.C. Fuller wrote that Clausewitz was on a level with Copernicus, Newton, and Darwin, and T.E. Lawrence praised Clausewitz’s work as far superior to any other, subconsciously inspiring him in his own thinking.

Later, two of the most influential strategic theorists of the post-Second World War period stated that Clausewitz had no peer concerning the subject of war and conflict. Bernard Brodie concluded: “...[that] his is not simply the greatest book, but the only truly great book on war.”2 Colin S. Gray compares Thucydides, Sun Tzu, and Clausewitz, and unequivocally privileges Clausewitz over his two predecessors.3 Finally, and most recently, the British philosopher W.B.Gallie wrote in 1995 that On War was the first, and, to date, the only book of outstanding intellectual eminence published on the subject of war

The subject of this praise, General Carl von Clausewitz (1780-1831), joined the Prussian army in 1792. He fought against the French Revolutionary and Napoleonic forces until the Battle of Waterloo in 1815, participating in several major battles, including Jena and the Battle of Nations. He was a man of a particularly philosophical bent, and he read voraciously and broadly, far beyond the field of military history. In 1818, Clausewitz was appointed Director of the Prussian War Academy in Berlin, during which period he composed On War. This work, the crowning jewel in his œuvre, has been enormously influential ever since. It would not be an exaggeration to say that the ideas of Clausewitz flow like a subterranean river through all of modern military thought.

Clearly, it is the substance of Clausewitz’s thought that accounts for his importance, not only for military doctrine but with respect to strategic theory as well. In the 21st Century alone, no fewer than seven books have been published in English dealing exclusively or extensively with this issue.

In 2001, the third edition of Michael Handel’s Masters of War: Classical Strategic Thought was released. Handel compares Sun Tzu, Jomini, and Clausewitz, and, in this writer’s view, he justifiably consigns the Swiss Jomini to history, effectively dismissing his relevance for the present. Handel then argues that Sun Tzu sought to teach how to fight wars efficiently, whereas Clausewitz intended to demonstrate how to fight wars effectively.

In the same year, Azar Gat’s A History of Military Thought: From the Enlightenment to the Cold War, appeared. This book is exceptionally valuable for two reasons. First, it compares Clausewitz’s thought to the military school of the Enlightenment (1687-1789), and it examines his profound influence during the 19th and 20th Centuries. Second, Gat’s treatment of the whole period is done in the context of intellectual history. Positivism, Romanticism, Social Darwinism, Marxism, Fascism, and Liberalism are all related to how military theory has been shaped over the past 300 years. It is an essential read for anyone wanting to understand Clausewitz within the sweep of intellectual history.

In 2002, a German scholar, Beatrice Heuser, published Reading Clausewitz, a book not only on how to read Clausewitz but also dealing with how others have read him. She identifies all of Clausewitz’s major themes and how individuals as varied as the German masters of warfare of the late 19th Century, through Lenin and Mao Zedong, to strategists of the nuclear age, have interpreted him. Heuser critically assesses these interpretations while guiding the reader through some of Clausewitz’s most difficult ideas with clarity and comprehension.

Two years later, an Australian, Hugh Smith, published On Clausewitz: A Study of Military and Political Ideas. This book has a textbook-like quality – clearly written and very well organized. Smith both sets out the Prussian’s ideas within the context of the revolution in war in his time, and then goes on to examine his relevance to the transformation of war in our own time. His treatment of the interaction between politics and war is insightful, and it amply demonstrates Clausewitz’s contemporary relevance.

Finally, in 2007, four new books appeared that, taken together, deal comprehensively with all of Clausewitz’s thought. Peter Paret’s Clausewitz and the State (1976), undoubtedly the best biography of Clausewitz written in English, was issued in a second edition with an extensively revised preface. Clausewitz’s Puzzle, by the German Clausewitzian scholar Andreas Herberg-Rothe, is a philosophical examination of some of Clausewitz’s main themes. Herberg-Rothe’s basic thesis is that Clausewitz’s political theory of war emerged from his personal experience in, and study of, the three battles of Jena, Borodino, and Waterloo.

The last two books of the seven are authored or co-edited by the outstanding British historian, Hew Strachan. Carl von Clausewitz’s On War: A Biography is actually one of a series of “Books That Shook the World;” a series that includes studies of Plato’s Republic, Adam Smith’s Wealth of Nations, and Machiavelli’s The Prince. This alone represents yet another testimonial to Clausewitz’s continuing importance. The primary purpose of Clausewitz’s On War is to understand the origins of Clausewitz’s thoughts, their evolution, and the varied forms in which they manifest themselves in his most important book. Each generation, according to Strachan, has read Clausewitz differently, but not necessarily inaccurately. Strachan admonishes us to regard the unfinished nature of On War (Clausewitz died before his final revisions) not “...as a source of frustration but of joy. Its author never stopped asking questions, not simply of his own conclusions but also of the methods by which he had reached them.”4

Strachan’s other 2007 book, Clausewitz in the 21st Century, co-edited with Andreas Herberg-Rothe, is a very valuable contribution to Clausewitzian studies, and it contains chapters by 16 distinguished scholars – British, German, American, French, Dutch, and Argentinian. All successfully demonstrate Clausewitz’s continuing utility in the current century. Three are of especial interest – Alan Beyerchen’s, “Clausewitz and the Non-Linear Nature of War: Systems of Organized Complexity,” Herfried Munkler’s, “Clausewitz and the Privatization of War,” and David Lonsdale’s, “Clausewitz and Information Warfare.” Beyerchen demonstrates conclusively that Clausewitz anticipated much of today’s discussion of systems theory and complexity theory and their relationship to war. Munkler extends this argument, demonstrating that Clausewitz’s theory allows for the possibility of today’s so-called “new wars” to a much greater extent than Martin Van Creveld (The Transformation of War) and Mary Kaldor (Old Wars-New Wars) have acknowledged. Lonsdale effectively refutes those proponents of the RMA who have argued that Clausewitz is far less relevant in an era when technology can “lift the fog of war,” and can conceivably be conducted virtually without bloodshed.

These seven books truly deepen our understanding of Clausewitz’s theory of war and how it continues to inform us concerning the character of armed conflict in our own time. All of them elucidate Clausewitz’s contention that while the character of war inevitably varies with the age, its nature remains the same. Existentially, it is an act of violence to compel our opponent to our will, while instrumentally, it is the continuation of policy with the admixture of other means. Nonetheless, I would argue two gaps in a complete understanding of Clausewitz are not sufficiently addressed in these books. The first relates to the intellectual context of his period and how that shaped his thinking. The second concerns the failure to explore fully the dual nature of strategy that Clausewitz was the first to identify.

Several of these authors acknowledge that Clausewitz was influenced by the Romantic Movement (1770-1840), but each accords equal or more weight to that of the Enlightenment, and to Newtonian science. On the contrary, I believe Romanticism had a far more profound impact upon Clausewitz’s thinking, an influence that helps explain both his concept of Absolute War and its relation to real war, as well as his conception of war as a non-linear phenomenon.

None of the authors discussed in this essay appears to have accessed the recent, deeply probing scholarship dealing with Romanticism. A study of the work of Isaiah Berlin, Jacques Barzun, Terry Pinkard, and particularly, Frederick Beiser and Manfred Frank, is essential to acquire a full appreciation of this pan- European movement and its intellectual relationship to the Prussian theorist.

Painting Napoleon at the Battle Jena, 1806 by Horace Vernet

Erich Lessing/Art Resource 211732

Napoleon at the Battle of Jena, 1806, by Horace Vernet.

With regard to the significance of Romanticism, one eminent intellectual historian has situated the movement as a revolutionary turning point in the history of Western thought. Isaiah Berlin argues the first turn occurred at the end of the 4th Century BC, when the philosophical schools of Athens ceased to conceive of individuals as intelligible only in the context of social life. The second turning, inaugurated by Machiavelli, involved his recognition that there is a division between the natural and the moral virtues, the assumption that political values are not merely different from, but may, in principle, be incompatible with Christian ethics. The third great turning point – which Berlin argues was the greatest – was conceived toward the end of the 18th Century, with Germany in the vanguard. Romanticism has produced vast and incalculable effects, Berlin says, including the very assumptions underlying Western thought.5

Clausewitz certainly read some of the leading Romantic artists and philosophers intently before the Battle of Jena (1806), especially Holderlin, Schiller, and Goethe. Afterwards, during his ‘house arrest’ in France, Clausewitz stayed with the Romantic author Madame de Stael. Here, he met and befriended a towering figure in the movement, Wilhelm Schlegal. When he returned to Berlin in 1808, Clausewitz joined the Christian German Symposium. A list of its active participants reads like a veritable Who’s Who of German Romanticism. Later, when Clausewitz returned yet again to Berlin (1818-1830) to command the War Academy, he interacted with other major Romantic figures, including Georg Hegel.

In his Battle: A History of Combat and Culture From Ancient Greece to Modern America John Lynn assesses the influence of these German philosophers and artists upon Clausewitz, and he concludes that although no single individual fashioned military Romanticism, von Clausewitz towered above all other military Romantics – so much so that lesser contributors practically disappear from view.

The Romantics rejected what they considered the desiccated rationality of the Enlightenment, and its emphasis upon Empiricism and its Materialism. The philosopher Fredrick Schelling, for example, launched an all-out assault upon the mechanistic science of the 18th Century. In addition, the Romantics sought a philosophical solution to the dualism inherent in the prevailing Cartesian paradigm of nature. They produced a philosophical articulation of the Romantic vision of the ultimate integration of all the particularities or bifurcations of reality in the concrete, dynamic totality of the ‘Concept’ (Begriff in German). The pivotal term ‘Concept’ means the purpose and the essence of a thing, its formal final cause. Romantics held that the object of both artistic expression and philosophical and scientific analysis was the ‘Concept’ that incorporated both the universal and the individual. The ‘Concept’ is the genuine first, and things are what they are through the action of the ‘Concept,’ imminent in them, and revealing itself in them.

Clausewitz was hugely attracted to this position in order to solve his own theoretical problem. He had determined that there were two fundamental kinds of war – essentially, unlimited and limited. However, his theory required that these kinds of war be unified in some way, subsumed in a greater, non-dualistic whole. His concept of Absolute War, his Begriff, was the solution. Whether any particular war was more or less limited, its essence remained the same as expressed through the ‘Concept.’ And this essence was what Clausewitz called the “wondrous trinity” – composed of primordial violence, hatred, and enmity, which are to be regarded as a blind natural force; of the play of chance and probability, within which the spirit is free to roam; and of its element of subordination, as an instrument of policy, which makes it subject to reason alone.

More important for Clausewitz’s contemporary relevance is the fact that Romantic science was thoroughly organic. The Romantics replaced the concept of mechanism with that of the organic, elevating it to the chief principle for integrating nature. They did not exclude mechanical explanation, acknowledging that mechanical explanation is perfectly valid of ‘all of the parts within the whole,’ but it is inadequate from the standpoint of the whole itself. This organicism was also naturally developmental, diachronic as opposed to nomothetic. This had a profound influence upon the Romantics’ view of history, and it led to the emergence of historicism, an approach to history apparent throughout On War. Romantic biologists like Goethe maintained that the aesthetic comprehension of the entire organism or of the whole interacting natural environment would be a necessary preliminary step in the scientific analysis of respective parts. Both in art and in science, comprehension of the whole had to precede that of the parts. This is exactly how Clausewitz conceived of war:

“War should be conceived as an organic whole whose parts cannot be separated, so that each individual act contributes to the whole and itself organizes in the central Concept.”6

This organic conception of war meant that this activity was part of a human activity system, a social activity. It was a complex system rather than a complicated system, and like all complex systems it was non-linear:

“War belongs to the province of social life. War is not an activity of the will exerted upon inanimate matter like the mechanical arts, or upon a living but passive, yielding subject, like the human mind and human feeling like the fine arts, but against a living and reacting force.”7

In many important respects, Romantic science anticipated today’s investigation of complexity theory. Clausewitz was clearly, quite consciously, dealing with what the American mathematician, Warren Weaver, called “organized complexity.”8 Alan Beyerchen supports this view, and he asserts that On War is suffused with the understanding that every war is an inherently non-linear phenomenon.9 In a profoundly unconfused way, Clausewitz understood that seeking exact, analytical solutions does not fit the non-linear reality of the problems posed by war.

Turning now to the second gap in our understanding of Clausewitz, we need to examine the man’s sophisticated treatment of strategy, which he defined with elegant simplicity as the use of engagements for the political purpose of the war. It is uncontroversial to assert that Clausewitz believed there were two kinds of war. The first kind set objectives that could be met only by the complete defeat of the opponent’s armed forces and by rendering him prostrate. The second kind was more limited, requiring only that the opponent be enticed to the negotiating table. But Clausewitz’s explanation for how this duality affected strategy is far less well understood.

In the case of unlimited war:

“The absolute form of strategy contains a host of interactions, since the whole series of engagements is strictly speaking, linked together. In view of all these intrinsic characteristics of strategy, we say there is only one result that counts – final victory. In unlimited war we must always keep in mind that it is the end that crowns the work. Within the concept of unlimited war, then, strategy is indivisible and its component parts, the individual victories, are of value only in relation to the whole.”10

When the political objectives were less absolute, war would be limited and a completely different strategic system should be employed. Again, according to Clausewitz:

“Contrasting with the concept of unlimited strategy, there is another view, no less extreme, which holds that war consists of separate successes, each unrelated to the next, as in a match consisting of several games. The earlier games have no effect upon the latter. All that counts is the final score and each separate result makes its contribution toward this total.”11

Clausewitz concludes this discussion of the two kinds of strategy by stating categorically that one must act upon the principle of using no greater force and setting no greater military aim than would be sufficient for the achievement of the political purpose.

General Tommy Franks

DVIDS image 37950

General Tommy Franks.

Throughout the 19th Century, military doctrine in the West focused upon the first kind of strategy identified by Clausewitz. The result was a ubiquitous search for the decisive battle, regardless of the political goal. However, in the early 20th Century, one theorist, the German Hans Delbruck, advised: “...[that] founded on the teaching of Clausewitz, I have established that there is a dual nature of war and thus also of strategy. One can be called the strategy of annihilation; its exclusive means is the destruction of the inimical armed forces in battle. The other sort can be called the bi-polar strategy. Apart from the battle it has a number of other means.”12 Now, Delbruck was not widely read, and, by and large, the 20th Century adhered to the concept of strategy as one which, whatever the political goals set, sought decisive military victory in battle. This, of course, was appropriate in the circumstances surrounding the First and Second World Wars, but it was decidedly not the case in Korea and Vietnam, for example. With the advent of nuclear weapons, moreover, strategic theorists such as Bernard Brodie, Henry Kissinger, and Colin Gray began to develop concepts of limited war derived from Clausewitz’s second strategic system.

In the post-Cold War era, there is little doubt that the strategy of annihilation may, at some future date, have utility, but in the current geo-strategic security environment, it has none. In today’s scenarios of irregular warfare the bi-polar strategy is the only one that is relevant. Strategists revert to the battle pole as required, but simultaneously or sequentially, on the non-battle pole, with a wide variety of other means to achieve political success. As General Sir Rupert Smith concluded: “We are now in a new era of conflict, in fact, a new paradigm, which I define as “war amongst the people,” one in which political and military developments go hand in hand.”13 {in other words, a bi-polar strategy} Furthermore, according to Smith, the ends for which we are fighting are changing from the hard objectives that decide a political outcome, to those of establishing the conditions in which the outcome may be decided.

Recognition of the nature and modalities of the bi-polar strategy is by no means universal to date. As Hew Strachan points out in Clausewitz’s On War, clearly General Tommy Franks conceived of his job as prosecuting a strategy of annihilation. His political and military masters in Washington were equally confused, and the “...declaration of the end of major combat operations” was designed to signal a decisive victory, leaving the “pacification” of Iraq to others.14 A proper understanding of the bi-polar strategy would have made clear that General Franks was conducting one early campaign on the battle pole at the operational level. Subsequent campaigns would flow continuously from there, and would necessarily involve both poles, with the emphasis swinging progressively to the non-battle pole as the security situation improved.

Notwithstanding the two gaps in the coverage of Clausewitz contained in the seven texts reviewed herein, they remain invaluable in rendering the Prussian theorist both intelligible, and, above all, relevant. Unfortunately, Clausewitz is seldom studied in Canada, and therefore, neither Clausewitz nor these valuable books will likely be widely read. This is a situation that should be rectified in the CF’s professional development system. Currently at RMC, for example, Clausewitz only appears in the conventional pantheon of military thinkers from Sun Tzu, through Jomini, Mahon, and beyond. In fact, all cadets should be introduced to Clausewitz, regardless of the program they are following. Subsequently, all officers attending Staff College should then encounter Clausewitz again being taught at a higher, more sophisticated level. It is probably at this level that On War should become required reading. He should be studied again at the war college level, this time, supplemented by the insights provided by some, or all, of the texts covered in this essay.

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Lieutenant-Colonel (ret’d) L. William Bentley, MSM, CD, PhD, is Head of the Leadership Theory Section of the Canadian Forces Leadership Institute in the Canadian Defence Academy.


  1. Colin Powell, My American Journey (New York: Ballantine, 1995), p. 207.
  2. Carl von Clausewitz, On War, edited and translated by Michael Howard and Peter Paret (Princeton: Princeton University Press, 1976), p. 52.
  3. Colin S. Gray, Fighting Talk (London: Praeger, 2007), p. 32.
  4. Hew Strachan, Clausewitz’s On War (Vancouver: Douglas and McIntyre, 2007), p. 193.
  5. Peter Watson, Ideas: A History From Fire To Freud (London: Weidenfeld & Nicholson, 2005), p. 607.
  6. On War, p. 607.
  7. Ibid., p. 149.
  8. Warren Weaver, “Science and Complexity,” in American Scientist, Vol. 36 (1948), p. 540.
  9. Alan Beyerchen, “Chance and Complexity in the Real World.,” in International Security, Vol. XVII, Winter 1992-1993, p. 74.
  10. On War, p. 582.
  11. Ibid.
  12. Quoted in Beatrice Heuser, Reading Clausewitz (London: Pimlico, 2002), p. 109.
  13. General Sir Rupert Smith, The Utility of Force (London: Allen Lane, 2005), p. xiii.
  14. On War, p. 4.

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