In Rebooting Clausewitz: On War in the 21st CenturyChristopher J. Coker aims to show how Carl von Clausewitz’s 1832 classic On War still contains important insights for our contemporary moment. While modern readers may not always agree with Clausewitz’s arguments, this work offers a good starting point for identifying elements that can illuminate discussions of war and peace today, finds Roberto A. Castelar

Rebooting Clausewitz: On War in the 21st Century. Christopher J. Coker. Hurst. 2017.

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Carl von Clausewitz’s On War (1832) is considered one of the most important classical works on the philosophy of war. It is a difficult and dense book that few dare to explore entirely, but many of its ideas have become widely known, principally that famous aphorism: ‘war is the continuation of politics by other means’. However, it could be suggested that, at first sight, the relevance of this work is merely historical. The phenomenon of war has been radically transformed since Clausewitz’s time: how could his ideas remain significant in an age of nuclear deterrence and asymmetrical warfare?

Christopher Coker’s Rebooting Clausewitz: On War in the 21st Century aims at convincing us that On War still contains important insights for our times. The primary audience of the book seems to be students at defence colleges, but its style is friendly to non-specialists and may prove illuminating for any reader. Coker develops his argument through three fictional dialogues in which Clausewitz is made to discuss aspects of On War and recent military events, such as the wars in Afghanistan and Iraq, with contemporary military scholars and students. These are supplemented by short essays about Clausewitz’s life and relevance.

Coker avoids the tendencies of both scholars who treat Clausewitz as the last word in military topics and those who dismiss him out-of-hand. Clausewitz, he argues, is relevant because ‘he knew more about war than anyone else’ (xiv), and because there are points in On War that have not been properly explored. He goes on to demonstrate how many of Clausewitz’s observations seem to be confirmed by modern sciences, such as social psychology, evolutionary biology, cognitive science and even business strategy. Yet, he is ready to admit that Clausewitz’s theory is incomplete, and this is often attributed to the state of science in his time, especially the absence of Charles Darwin’s theory of evolution (70).

Image Credit: Red Cross Bookshop, 2008 (Qtea CC BY 2.0)

The structure of the book is easy to follow, but there are, in my view, a number of shortcomings in style. The initial theme of the fictional dialogues, the uses of a theory, is rather too abstract; the discussion about the essence and character of war or the theme of the Napoleonic wars would have been a better start. The flow of the topics is a bit disorganised and Coker tends to digress from the main discussion without necessity, even if the reader may find these highly informative. But the shortcomings are balanced by rich content. Coker displays an impressive knowledge of many advances in modern sciences, and this is coupled with engaging illustrations taken from contemporary English literature.

Overall, Coker is successful in connecting many elements of Clausewitz’s work with contemporary debates, and in showing how these elements might illuminate our discussions, even if we might not agree with Clausewitz’s contributions. One of the most interesting points is the claim that Clausewitz has, in fact, much to tell us about guerrilla and asymmetrical wars (85), despite the differences between his and our times. Clausewitz is also shown to be highly relevant for the problem of the relation between theory and practice: not only for people involved in the military, but for everyone. He rejected the imposition of rigid theoretical systems upon reality, stressing the uncertainty of the world but also insisting on the necessity of theories as guides for action.

There are some issues of interpretation. Coker sees Clausewitz as standing firmly in the Enlightenment tradition, given his belief in human autonomy and progress and his dependence on Immanuel Kant, although he admits some influence of the Romantic movement, particularly in regard to the impact of human psychology. However, I think that Clausewitz’s emphasis on history, the particular, experience and uncertainty are less characteristic of the mainstream Enlightenment tradition than other competing traditions, even if Clausewitz eschewed the mysticism and emotionalism of the Romantics. But this question is not, of course, necessarily related to Clausewitz’s contemporary relevance.

A more difficult aspect concerns Clausewitz’s relation to the ethics of war. Most of us modern readers do not argue so much about why the US failed in Afghanistan and Iraq; we argue more about whether these wars were morally permissible, we strive for a world in which they are prevented and we care for the human suffering generated by them. But these concerns do not have much space in On War. How could it help us in our deliberations? About Clausewitz’s silence on human suffering in war, Coker cautions us not to judge the people of the past according to present concerns (10), which is certainly good advice, but not a convincing reason to think that their thought is relevant to us.

Regarding the ethics of war, a more sophisticated explanation is nonetheless given. Clausewitz is as much concerned about the control of war as modern readers may be, but he represents an alternative approach: he is not interested in judging war according to timeless moral principles, but rather in showing how war develops in practice and in illustrating what we can do about that. According to him, it is through politics that we can prevent war from escalating and control it (26). He approached then what we, roughly speaking, would call ‘realism’ today. However, this take on the issue might not be appealing for those of us who remain committed to general moral principles to judge war regardless of place or time.

But Clausewitz’s central insight about the role of politics in preventing the escalation of conflicts and putting limits to military action might still be very useful. As Coker shows, despite his widespread fame, this role of politics in Clausewitz has not been seriously considered, even in very recent conflicts (117). Politics is often said to end where conflicts start; wars are seen as the result of the failure of politics. Clausewitz states that they are continuous, but this does not only mean that politics is often to be blamed for war, but also that we can use politics to control and contain it.

It is certainly a point that needs to be reworked – by ‘politics’ Clausewitz did not mean ‘democratic politics’ as we would likely mean it – but it can still orientate our deliberations about the character and future of war and peace. This fact demonstrates that, even if we perceive a great distance between our public discussions about war and Clausewitz’s concerns, there are elements in his work that we can expand, develop and modify to benefit our own purposes, and Coker’s book is a good starting point for identifying these.


Roberto A. Castelar is a graduate from the Central European University in Budapest. He specialises in Political Theory and the History of Modern Political Thought. Read more by Roberto A. Castelar.

Note: This review gives the views of the author, and not the position of the LSE Review of Books blog, or of the London School of Economics. 

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