HomeAU PressBook ReviewsDisplay Review

Air University Press

Decoding Clausewitz: A New Approach to On War

Decoding Clausewitz: A New Approach to On War by Jon Tetsuro Sumida. University Press of Kansas, 2008, 224 pp.

Given the complexity of Clausewitz’s ideas and the ongoing debate surrounding their meaning, it is difficult to speak of a “conventional wisdom” regarding the content and practical utility of On War. Nevertheless, students of Clausewitz have traditionally accepted three general propositions regarding his inimitable study of conflict. First, most believe that Clausewitz died before revising the entirety of On War to his satisfaction. Thus, significant portions of the book express his ideas in an incomplete or embryonic form. Second, scholars have emphasized the importance of the book’s first chapter, which represents Clausewitz’s mature conception of the dynamics of conflict. Third, Clausewitz’s theory is generally viewed as a description of war as a phenomenon rather than a prescriptive guide to its conduct. In this provocative new analysis, Jon Tetsuro Sumida challenges all three propositions and in the process adds significant new weight to arguments for the contemporary relevance of On War.

The book comprises four chapters. The first three effectively set the stage for Sumida’s thesis by critiquing the way in which other writers have interpreted On War, examining the impact of Clausewitz’s own experiences on his ideas about war, and comparing these ideas to those of an eclectic range of later scholars, including Charles Sanders Peirce, Ludwig Wittgenstein, and R. G. Collingwood. In the final chapter, Sumida accepts Azar Gat’s contention that by the time Clausewitz died in 1831, “On War was complete with respect to its general form and major arguments” (p. 181). Consequently, he maintains that readers cannot understand Clausewitz’s ideas fully if they focus only on such selected portions of the book as its first chapter. Sumida discusses at length the arguments developed in the final three books of On War, particularly that regarding the relationship between attack and defense. Rather than an incomplete sketch with limited applicability beyond the watershed of the industrial revolution, he contends that this argument is fully developed, central to On War, and a useful tool in understanding contemporary conflict. Sumida explains Clausewitz’s assertion that the defensive is the stronger form of war, emphasizing the importance of guerrilla warfare. While some writers have dismissed On War as an obsolete treatise on conventional interstate wars, Sumida demonstrates that Clausewitz gave considerable thought to guerrilla tactics. Specifically, he viewed them as a valuable tool for the defender because they compel the attacker to disperse the attacker’s forces. This diminishes the advantages associated with the concentration of force, obliging the attacker to prolong the campaign. This in turn enervates the attacker’s political will, which is inherently weaker than that of a defender struggling to preserve its territorial integrity or perhaps even its existence. Thus, guerrilla tactics help the defender to sap the strength of its enemy until it can take the strategic offensive using conventional forces.

In addition to drawing new attention to an important but relatively obscure argument within On War, Sumida challenges prevailing views regarding the book’s purpose. Citing Clausewitz’s caustic dismissals of the prescriptive approaches of such theorists as Jomini and Bulow, scholars have long maintained that he doubted the possibility of establishing universal principles of war and sought instead to describe war as a phenomenon.

Sumida agrees that Clausewitz was skeptical of the practice of deriving general principles from the study of past campaigns, but he argues nonetheless that Clausewitz wrote On War “as a theory of practice rather than as a theory of a phenomenon” (p. 2). According to Sumida, Clausewitz believed that the study of history supplemented by the use of theory to fill gaps in the historical record would enable officers to recreate the decision-making process of commanders in past conflicts. This process would provide strategic and tactical insights to officers without significant command experience of their own. By the late 1820s, Clausewitz viewed this type of education as increasingly important to prepare a generation of Prussian officers who had not participated in the Napoleonic Wars for a possible conflict with a resurgent France.

At times, Decoding Clausewitz may frustrate readers interested primarily in the practical value of On War. To shed light on the content and purpose of Clausewitz’s study, Sumida detours through the ideas of a wide variety of writers, some of whom had no connection to or awareness of Clausewitz himself. In addition, scholars immersed in the contemporary debate regarding the fidelity of existing English versions of On War may challenge Sumida’s use of Sir Michael Howard and Peter Paret’s 1976 translation. For example, Sumida accepts the explanation of Howard and Paret of the purpose of theory as being to maintain “a balance” between the three aspects of Clausewitz’s trinity. Christopher Bassford, however, has argued that this interpretation encourages the equation of theory with doctrine and that a more accurate translation would have theory “floating among” the three tendencies of the trinity. This rendition, he contends, conveys more accurately Clausewitz’s limited expectations for theory, given the inherently volatile and unpredictable nature of war.

Overall, however, neither Sumida’s use of the Howard/Paret translation nor the diversity of the scholarship covered in the book diminishes the significance of his principal arguments. Sumida’s discussion of Clausewitz’s view of the relationship between attack and defense demonstrates the value of On War in illuminating the dynamics of contemporary conflicts, even those in which guerrilla tactics methods are prominent. More broadly speaking, Sumida’s contention that the book contains a “theory of practice” strengthens the argument that the careful study of Clausewitz may help military and political leaders think more effectively about war.

Nikolas Gardner, PhD

Air War College


"The views expressed are those of the author(s) and do not reflect the official policy or position of the US government or the Department of Defense."

Strategic Studies Quarterly (SSQ) and the Air & Space Power Journal (ASPJ) publish book reviews to inform readers and enhance the content of articles in the journals.