If poor Douglas Haig is one of history's most maligned military commanders, then Carl von Clausewitz must be one of its most misunderstood and most criticised military theorists. His greatest work, On War, is variously said to be an amoral legitimisation of war as a political tool, a paean to the reckless use of disproportionate force to overcome the enemy, and so devoted to the offensive as the only means to victory that its influence indirectly caused the slaughter of the First World War. It is often unfavourably compared to Sun Tzu’s The Art of War, which typically takes the form of declaring that Sun Tzu’s approach to strategy took the form of winning wars without fighting battles, while Clausewitz’s “inelegant” approach knew nothing but the battle.
On War is not a work that aims to legitimise war, nor is it a book that preaches the utter destruction of the enemy regardless of circumstances. Such criticism comes from a total misunderstanding of Clausewitz, usually because those who criticise him have never actually read Clausewitz. The comparison to Sun Tzu usually comes from armchair strategists who, in some bizarre act of military Orientalism, view the “mystical Eastern wisdom” of an easily-read-in-an-afternoon book of common-sense maxims to be superior to a well-researched, well-supported academic text that doubtless they have not bothered to read. However, unfounded criticism of Clausewitz has even come from academic quarters, and the late great British military historian John Keegan even wrote an entire book, A History of Warfare, with the aim of disproving Clausewitz’s most infamous declaration, “war is a mere continuation of policy by other means”. As we will see, nearly all of these criticisms are invalid if we simply return to the text of On War.
Carl von Clausewitz was born in 1780 in Prussia. He joined the Prussian Army in his early teens, and saw service against the French Revolutionary armies in the War of the First Coalition until Prussia’s withdrawal from the war in 1795. During Prussia’s ten-year peace, he studied strategy and philosophy at the new Prussian Military Academy in Berlin, and came under the patronage of Gerhard von Scharnhorst. Arguably the true formative moment in his career, however, was his witnessing of the catastrophic Prussian defeat by Napoleon at the Battle of Jena-Auerstedt in 1806. At the age of 26, he was one of 25,000 Prussian prisoners taken during the battle and only returned to Prussia in 1808, where he became hugely active in the reform of the Prussian Army, which had been exposed as a museum piece by its defeat. In protest against the Prussian alliance with France in 1812, he and thirty other officers deserted to Russia and (despite not speaking a single word of Russian) served as a staff officer opposing the French at the Battle of Borodino. Following the French defeat and Prussia’s withdrawal from the alliance, Clausewitz returned to Prussia and was enormously influential in developing the campaign plan, fought by his and Scharnhorst’s reformed army, which defeated Napoleon in 1814. Following Napoleon’s final defeat at Waterloo, he was posted to the Prussian War College. However, he never had the chance for glory in a field command, and so apparently sought to make an impact in the field of military theory instead. He died in 1831 aged 51 coordinating Prussia’s response to a cholera outbreak.
Clausewitz was thus witness to the greatest wars in a century, the utter shattering of the old military order by the new at Jena-Auerstedt, and the military impact of such new ideologies as revolutionary fervour and popular nationalism. This last point is hugely important in explaining Clausewitz’s philosophy of war, in particular the meaning of his most infamous statement; “war is a mere continuation of policy by other means”.
That statement is not, as many have declared, an amoral attempt to legitimise war through the lens of realpolitik. Furthermore, it is not Clausewitz’s only definition of war, as John Keegan believed when he wrote A History of Warfare. Keegan points out that this statement implies that war is fought with the rational use of force, for entirely rational aims, and assumes the existence of states. However, giving the examples of Easter Island and the Yanomami and Maring peoples, he points out that war is entirely possible within stateless cultures. Furthermore, he points out that war is inherently fought with an animalistic savagery and irrational levels of violence, and is even often fought for irrational ends. The most obvious example of this would be the German war effort in the Second World War, where rational calculation (as in fact reflected in their logistics plan for Operation Barbarossa) would have pointed out that it was impossible for Nazi Germany to defeat Soviet Union even on its own. Irrational emotion replaced rational calculation, and so death and misery for millions followed.
However, Keegan’s conclusions do not refute Clausewitz, since “war is a mere continuation of policy by other means” is not Clausewitz’s only definition of war. In fact, when considered with Clausewitz’s other definition of war, they reinforce Clausewitz’s thought. “War is a mere continuation of policy by other means” is a logical antithesis to Clausewitz’s first definition of war (and how this is not the better-known definition of war I have no idea, since it appears on the very first page of On War): “war is an act of violence intended to compel our opponent to fulfil our will.” The former definition of war implies one fought entirely with reason and rationality in mind, while the latter implies a war fought to the very end with the “utmost exertion of powers” and the “utmost use of force” to totally “disarm the enemy” (Clausewitz’s three reciprocal actions). As Clausewitz actually points out in On War, both extremes are impossible: if a war is fought for political goals, once those goals are achieved there is no need to subject the enemy to debellatio. On the other hand, uncertainty and emotion mean that war can never be fought according to pure reason, and so it will inherently include elements of savagery.
This understanding of the different types of war is often forgotten about when discussing Clausewitz, even though On War is as much a work of philosophy as it is a one of strategy. Such a philosophical discussion seems rather woolly for a book designed to be a practical military text, but when combined with the second of Clausewitz’s two most famous ideas, it can give an astonishingly insightful view of how a war might be prosecuted. That second idea is the “fascinating trinity”.
This trinity is “composed of primordial violence, hatred, and enmity, which are to be regarded as a blind natural force; the play of chance and probability, within which the creative spirit is free to roam; and its element of subordination, as an instrument of policy, which makes it subject to pure reason.” War, therefore, is fought with the violent emotion of both soldiers in battle and the people of the state, with calculated risks and chance made more acceptable by proper intelligence and military planning, and finally with a political object in mind which defines operations. This trinity has often been described as the will of the people, the power and ability of the army, and the aims of the government. However, this is a misleading translation of the “fascinating trinity” as this definition can refer only to war at a strategic level, while Clausewitz’s original philosophy can work at any level of war.
When we combine the trinity with the two definitions of war given above, we can form a picture of how a war may be conducted. When emotions and passions are high, chance and risk can be reduced (or it is perceived that they can be reduced), and the political object is grand, war will be conducted closer to the absolute, with the aim of “disarming the enemy” and “compelling the opponent to fulfil our will”. But if passions are low, military motives are weak and the political object is less important, then the war will be conducted more rationally, perhaps even half-heartedly, where the needs of the political object are kept foremost in mind. This has profound implications for our modern wars, which are likely to be far from home, long-term, and unconventional. Consequently, will and passions will be low, uncertainty will be high, and the political object will be less important, so the war will likely be fought, not to an end, but to a state politically acceptable to the government. We have seen well in recent months the limitations of this state of affairs in Iraq and Afghanistan. If such a state of affairs exists in a conventional war, however, then Clausewitz explicitly points out that through skilful political and military manoeuvre, the political object may be attained bloodlessly. For all the unfavourable comparisons between Sun Tzu and Clausewitz, this all sounds rather similar to Master Sun’s “to win without fighting is the acme of skill”.
Such comparisons are no doubt brought about by Clausewitz’s definition of strategy, which he considers to be “the employment of the battle as the means towards the attainment of the object of the war.” How does this relate to his consideration that it is possible to win a war bloodlessly, as above? Clausewitz believed that “the bloody solution to the crisis” could be delayed, or even brought on to favourable ground, but could not be avoided if delay would no longer be continued “without ruinous disadvantage.” Clausewitz recognised that even in the bloodless victories he refers to, the commander only wins by creating and being aware of the threat of battle, for combat is “the first-born son of war”. During the War of the Third Coalition, Napoleon may have won the Ulm Campaign and forced the Austrian surrender with minimal loss to himself, but he did so by threatening the Austrians with an impossible battle. Furthermore, if the enemy’s passions are inflamed, if he considers that he has a good chance of victory, and if he considers his own political object valuable, then he must be met in battle. To win without fighting may be the acme of skill, but to expect to do that in every war is to invite ruin.
Thus, such criticisms and comparisons are shallow, misleading, and brought about by reading the crib-sheet version of On War rather than the book in its entirety. In many ways not reading Clausewitz is understandable, because even the best English translations of his text are astonishingly dense. Sun Tzu’s pithy, blow-by-blow collection of easy-to-read “war for idiots” maxims is far more accessible. Additionally, Clausewitz died with On War incomplete, so it is inevitably read in an unedited form. This coupled with his dryer-than-dry prose makes it easy to see why Clausewitz is so often misunderstood.
In conclusion, Clausewitz is not the militarist monster many seem to believe. He did not recklessly preach war as a political panacea and seek to legitimise it. Nor did he demand the utter destruction of the enemy in a single contest of strength. He saw war as something intrinsically savage but also inevitably fought for a political end and limited by politics. Those militarists who followed after his death, who cited Clausewitz as justification for whatever war they deemed to start and whatever strategies they used, misinterpreted Clausewitz as badly as those modern writers who see his thought as that of an inelegant thug bearing a hammer and seeing everything as a nail. Clausewitz must be read carefully, for that is the nature of how he wrote, but in the modern world he still has much to offer.
Carl von Clausewitz, On War
John Keegan, A History of Warfare
Sun Tzu, The Art of War