It is rare that PhD theses are a revelation, and this is such a one. It requires hard work to get there, but when it finally dawns on you what this is about, it will change the way you think, not only about Clausewitz, but about strategy making in general, its limitations and purposes. To get straight to the crux: should the aim dictate means, or must the means limit aims in strategy making?

To paraphrase Donald Rumsfeld, one goes to war with the forces one has, not with the forces one wishes one had. Unless a particular war is planned for and prepared for over the longest procurement cycle imaginable, when it breaks out, one is invariably not equipped as one would like to be. This was the recurrent theme in NATO planning from its earliest days: planners preferred to project the outbreak of war to five years’ time from when they were writing, when that next series of weapons systems would have entered NATO arsenals. Military planners in general never feel they are quite ready for the next war, an important factor which explains much about the »appeasement« policies of the British and French governments in the late 1930s vis-à-vis the dictators.

Along with procurement cycles (which were not yet factors in Clausewitz’s time) logistics are such a crucial limit on what one can aim for in war. Even today, in the age of air lift, logistics limit what is possible. When in 1999 NATO started its air campaign against Serbia, boots on the ground prior to a cessation of hostilities were ruled out because NATO’s Military Committee, chaired by German General Naumann (and Germans have learnt a thing or two about long-range logistics), could not see a way of supplying them, say, from bases in Albania, across the mountains, in summer let alone in winter. Twenty years on, the problem still obtains. Sure, if we are engaged in a war for survival, if nuclear weapons have not brought this war to a very quick end and it lasts long enough to go from research and development to large-scale production (as in the First World War with the »tank«), and if we pull all the stops, then the means can be subjugated, to some extent, to the ends. But even then, means are generally finite, geography usually matters, as does size. In short, means limit strategy, and that is a fact, not a matter of interpretation.

Take this one step up: the question whether aims can dictate means or means must limit aims is also about the role of the military and the role of the political leadership in strategy making. There has been a lengthy debate over recent years, spear-headed by Hew Strachan and supported by practitioners-turned-philosophers such as Generals (ret) Christopher Elliott and John Kiszely, who have shown that excessive military compliance with political instructions without close attention paid to how these could sensibly be translated into military action, given the context of means, has led to repeated disasters. This has come after decades of academic criticism of military insubordination and Caesarism (the aspirations of the military – mainly outside the Anglosphere – to take over governments). The consensus, today, has moved much further in the direction of saying ends depend on means, and can only be formulated in taking the means into consideration. Ergo, strategy should be based on a dialogue between military leadership and political decision-makers, but must not be a one-way process.

The debate was already fully present on both sides of the year 1800. It was, as the author shows, at the centre of a widely-read late 18^th-century publication by Adam Heinrich Dietrich von Bülow, and the scathing criticism to which Bülow was subjected by Prussian General Gerhard von Scharnhorst, the all-but forgotten Friedrich von Gaugreben, and Scharnhorst’s disciples Carl von Clausewitz and Otto August Rühle von Lilienstern. All four harped on about how »trivial« Bülow’s emphasis on the importance of logistics is, and on the inappropriateness of his attempts to capture its role mathematically, in terms of distances to magazines, transport, quantity etc. Yet as Arthur Kuhle shows, Bülow’s critics, in celebrating the triumph of the will and of the choice of ends over the constraints of means, prepared the way for ever more extreme forms of war, a first step down the slippery slope towards total war, and towards (Clausewitz-fan) Ferdinand Foch’s misguided belief that »victory is will [-power]«.

Kuhle has delved deeply into the literature surrounding the genesis of Clausewitz’s »On War«. Interpretation is not easy, as several key terms used over and over in that literature have since shifted significantly in meaning. One is »system« which was the big fashionable word of the late 18^th and early 19^th century, then meaning as much as »theory« or »paradigm«, but coupled with other words, such as »war«, could mean »strategy« or »basic principle of warfare«. So when Bülow wrote his »Spirit of the New System of War«, what he meant was »the new basic principle of warfare«. Bülow claimed to have discovered this in developing, at considerable length, a positivist theory about logistics: given the fact that armies tried to avoid living »off the land«, and to hard circumstantial factors of the time (roads, horsepower and -speed, length of time over which victuals could be preserved in storage sites), he argued that armies (on both sides of any war) would be limited in their movements by their distance from such magazines. He then went on to develop mathematical models concerning one’s own and the enemy’s distances from such magazines and supply routes, basically cautioning against overstretch.

Scharnhorst and Clausewitz both ranted against Bülow’s positivism which they took to stand for the theory that warfare could be reduced to positivist tenets. Both Scharnhorst but above all Clausewitz were against the blind application of rules (whenever A then B) in strategy making. Instead, they wanted officers to wise up to multiple considerations the relationship between which would depend on each particular war, which only the decision-maker of the day could fully understand. For war is a chameleon, a metaphor which we learn Clausewitz nicked, as usual without acknowledgement, from Friedrich von Gaugreben’s 274-page critique of Bülow’s »Spirit«. All three fought hard against the tendency in military training (which is much the same in Political »Science« today) to teach a set of rules that can be applied to any war (just as the Social »Science« approach tries to identify an ever larger set of theories about how all societies or all international relations, all inter-state wars, or all insurgencies »work«). Arthur Kuhle makes a credible case arguing that they threw out the baby with the bath water. Bülow’s critics over-emphasised genius and the freedom and will of the decision-maker, while loosing sight of real-world constraints which all hold. This should be borne in mind by those who think Clausewitz cannot be faulted, and has real implications (with the caveat of »generally, not absolutely always«) for strategy-making today.

But Arthur Kuhle’s book does far more than shine light on this particular debate. Above all, his book aims to rehabilitate Bülow whose »Spirit«, during his own life-time, was praised as the most important analytical work on war in existence. Kuhle shows that Bülow did not stop at promoting the imperative of assuring food supplies for the army to a cardinal factor in strategy making. He went further: in a publication of 1799 he espoused the idea that it would make sense for all states to spread to some »natural [geographic] limits« and that they would then seek to expand no further, creating necessary conditions for Kant’s perpetual peace (p. 227). This idea underlies the redistribution of territories envisaged by the Duc de Sully in his »Grand Design« of the early 17^th century, and the idea that France should attain its »natural borders« (preferably including holding the Rhine in perpetuity) flourished in the 18^th century.

For Bülow, this was a function of internal lines of supplies from supply bases to frontiers, but also of each army’s, and each polity’s, fundamental need for survival, which Kuhle calls the »principle of subsistence«. Bülow linked this with balance-of-power theories of his times by postulating that the »political system of Europe« in which »one great power can no more be destroyed without unsettling all the others, than a planet can be catapulted out of its position [in the solar system] without undermining the whole system«. From this Bülow deduced that higher diplomatic-political concerns might well dictate that the adversary should not be destroyed, but merely manoeuvred into a position where he might make concessions (and yes, Bülow is another contender to the claim of having discovered the primacy of politics over warfare).

Kuhle shows in the following, Bülow’s fiercest critics in fact espoused many of his ideas about distances from magazine or base to frontline and about enveloping an adversary along lines of attack etc. He also notes that their criticism of him may well have been driven by political opportunism, as Bülow in 1806 published a work on the campaign of 1805 ending in Napoleon’s triumph at Austerlitz, a work which was highly critical of the way in which Austria and Russia had fought against Napoleon. A few days after its publication, on 7 August 1806, Bülow was arrested and sentenced to six years of prison in Colberg. The charge of which he was convicted was his criticism of the Prussian king and of foreign heads of state and of leading officials (p. 376). A year later, he was handed over to the Russians and died in prison in Riga, from the effects of torture. It makes sense to think that it was in the interest of everybody – friends and critics alike – to distance themselves from Bülow.

What Kuhle is curiously silent about is the political background. In 1806, Napoleon had dissolved the Holy Roman Empire, and just as Bülow was being arrested for offending heads of state, Prussia was in the process of abandoning its former position of neutrality. On 26 August 1806, Prussian King Frederick William III issued an ultimatum to Napoleon, insisting he withdraw his forces to the West of the Rhine, or else Prussia would declare war. The result of that campaign, culminating in the battle of Jena and Auerstedt fought by Prussia with reasonably short supply lines in nearby Saxony, was a crushing defeat for Prussia. Neither Bülow’s prescriptions for perpetual peace resulting from polities living and letting each other live, nor his prescriptions for fighting with short supply lines worked for Prussia. No wonder the »war party« of the fanatically anti-French officers led by Scharnhorst henceforth had no sympathy for Bülow’s pacific ideas. While it took the war party another six years to sway the mind of the Prussian king once more to take up arms to join forces with Russia against Napoleon, Bülow’s ideas to them must have stood for Frederick William’s long clinging to neutrality before 1806, and after Jena and Auerstedt, his submissive behaviour towards triumphant France. In criticising Bülow, they likely criticised the pacific, defensive grand strategy associated with him – even if, paradoxically, the poor man had been sacrificed to the state interest of Prussia and its relations with Russia, the power that would eventually wear Napoleon’s forces down in the winter of 1812/1813.