Decoding Clausewitz: A New Approach to On War. By Jon Tetsuro Sumida. Lawrence: University Press of Kansas, 2008. Reviewed by Dr. Janeen Klinger, Professor of Political Science, US Army War College.


See also Dr. Klinger's article, "The Social Science of Carl von Clausewitz," Parameters, Spring 2006, pp.79-89.

Anyone seeking to write an original analysis of Carl von Clausewitz’s classic On War is undertaking a daunting task because the book has generated so much scholarly attention and extensive controversy. The new book by Jon Sumida, Decoding Clausewitz: A New Approach to On War, adds to this literature and claims to provide the most accurate interpretation to date. Dr. Sumida says his analytical perspective is unique in three ways: his belief that Clausewitz did in fact complete editorial work on the book; his emphasis on Clausewitz’s view that in war, defense is superior to offense; and his assertion that On War can only be understood as a theory of practice and not as a theory of a phenomenon.

Dr. Sumida argues that most scholarship concerning Clausewitz is inaccurate because it is based on the underlying assumption that the manuscript was unfinished. In a note thought to have been written in 1830, the year before he died, Clausewitz states that he was dissatisfied with most of the manuscript and would have to rewrite it entirely. Sumida believes the note was from 1827, which would have allowed Clausewitz ample time.

The consequence of the assumption that On War was unfinished distorted subsequent scholarship on Clausewitz. Sumida believes that scholars felt justified to pick and choose parts of the manuscript for analysis rather than engage it as a coherent whole. His criticism does not seem totally fair because it is surely legitimate for scholars to choose to narrow their focus regarding any classic work as complex as On War. For example, Sumida summarizes the work of Walter B. Gallie by suggesting that his assessment of Chapter 1 of On War is incomplete. As evidence, Sumida cites Gallie’s own statement regarding his intention to resolve the problems associated with the definitions of absolute and real war. Yet surely, for someone like Gallie who is primarily a scholar of philosophy and not a military historian, narrowly confining his analysis in a way to highlight philosophical issues is a justifiable academic approach.

The second analytical perspective that Sumida puts forward as unique is that Clausewitz saw defense as superior to offense. Sumida argues that the “great majority” of scholars ignored Clausewitz’s analysis of the defense and that as late as 1976, even with a revival of Clausewitz scholarship, his views on the defense were not well understood. On this point there is some credence to Sumida’s claim, because twentieth-century interpretations of Clausewitz were shaped by two factors. The first historic factor was the experience of the two World Wars, both of which were viewed as prompted by the German military implementing Clausewitzian doctrine. The second factor, related to the first and reinforcing it, was the popularity of the writings of Basil Liddell Hart that tended to characterize Clausewitz as a proponent of the Napoleonic offensive battle.

Despite these two factors and the strand of analysis that did emphasize the offensive doctrine of On War, it is not really accurate to say that the great majority of scholars ignore Clausewitz’s analysis of the defense. Sumida himself notes that even Hart recognized Clausewitz’s view that “the defensive was the stronger form of action” in his book The Defense of Britain, published in 1939. Moreover, this point was also disseminated through an essay by a German-American scholar, Hans Rothfels, published in the 1943 edition of Edward Mead Earle’s classic, Makers of Modern Strategy. Rothfels highlights Clausewitz’s views on the defense—specifically noting the advantages that Clausewitz believed to accrue to the victim of an attack.

The last perspective offered in Dr. Sumida’s decoding is that On War should only be understood as a theory of practice and not as a theory of phenomenon. Several points should be noted. It is not clear that one can neatly separate what constitutes a theory of practice from a theory of phenomenon. At a minimum, one would seem to need some sense of a theory of war as a phenomenon in order to derive a theory of practice. Sumida claims that the problem with interpreting On War as a theory of phenomenon is that by definition such a theory provides instruction on how to behave and is thereby prescriptive and alien to Clausewitz’s purpose. Yet scholars who view On War as a theory of phenomenon do not conclude that the book is prescriptive.

The strategy that Sumida follows to bolster his case concerning the kind of theory to be found in On War is to examine scholarly work that Sumida claims Clausewitz anticipated. The work of Charles Sanders Peirce, Ludwig Wittgenstein, and R. G. Collingwood is summarized to show how ideas expressed in On War foreshadowed subsequent philosophical developments. Especially important for Sumida is Collingwood’s notion of historical reenactment that Sumida believes parallels Clausewitz’s methodology for psychological reenactment of decisionmaking by the high command. Sumida believes that Clausewitz’s method is obscured by his use of inaccurate nomenclature and using the term “critical analysis” rather than “historical reenactment.” On this point, one might do well to apply a version of Occam’s razor that the simplest explanation is the best and that perhaps Clausewitz used the term “critical analysis” because that is what he meant to say. Sumida then goes on to summarize the similarities between Clausewitz and the three subsequent thinkers:

Like Clausewitz, all three thinkers problematized language with respect to communication of meaning about matters involving human behavior, distrusted the invention of technical vocabularies, were skeptical of the utility of theory that was based upon rules, and believed that experience can convey meaning in ways that language cannot.

Given Clausewitz’s life story and his own statements about his purpose for writing, it is hard to imagine that he saw his task as the one described by Sumida. Besides the fact that linkage with Peirce, Wittgenstein, and Collingwood seems a little forced, Sumida falls into a trap that is an occupational hazard for all Clausewitz scholars. Namely, that although much scholarship may indeed contribute to our body of knowledge and has academic value on that level, the analysis may not make On War more accessible to the general reader or military professionals. It was the latter audience that Clausewitz himself was most concerned to address. In the final analysis, Decoding Clausewitz is a useful reminder that Clausewitz’s great work is always worth rereading and is likely to continue to spark interest and controversy central to debates about war.