Decoding Clausewitz sounds like the book most students of Clausewitz would welcome—a concise, clear guide to an efficient, informed comprehension of a lengthy, formidably complex text. Professor Jon Sumida has written an original, argumentative, intelligent, disgressive, and interesting book, but he has not decoded Clausewitz, at least not in the judgment of this reviewer. A key weakness of the book is in its outright rejection of the scholarly consensus that at the time of the author's death, in 1831, On War was still a work in progress. Instead, Sumida accepts the 1989 argument of Azar Gat that Clausewitz had completed the most important revisions, and from this premise Sumida asserts that On War is a completed work, "an essentially sound representation of Clausewitz's considered views" (p. xv).
The limited documentary evidence points to a different conclusion. Marie, the widow of Clausewitz, who was closely involved in his work and published it posthumously in 1832 in ten volumes, described an undated prefatory note by her late husband as "very recent" ("sehr neuem Datum"), and placed it last in a sequence of four such notes, after a note dated 1827; scholars have agreed that 1830, when Clausewitz transferred from the War College to the artillery, and packaged, labeled, and sealed his papers, is a fair guess for the date of this final note, in which he says, "The first chapter of Book One [of Eight] alone I regard as finished." [End Page 642]
Gat and Sumida reject the weight of this evidence, and use textual comparison as well as ascribing "romantic" bias to those who accept the 1830 date, to conclude that the undated memo was written before 1827, and that between 1827 and 1831 Clausewitz was able to complete his planned revisions. Dating a memo may seem to be a trivial issue, but the pre-1827 dating of the undated memo leads Sumida to his basic conclusion, which this reviewer rejects, that On War is not a work still in progress in 1831, but a finished, coherent book.
This questionable assertion leads Sumida down some interesting paths in the four long chapters comprising his own book. In the first chapter, his criticism of the critics of Clausewitz, Jomini, and Liddell Hart, is no surprise, nor is his admiring treatment of the naval historian and theorist, Julian Corbett, a disciple of Clausewitz. But in Chapter 2, entitled "Scholars," his rough treatment of Raymond Aron and Peter Paret, stems directly from their [allegedly mistaken] belief that On War was still unfinished in 1831, and from their acceptance of the author's words in the undated note that only the first chapter "I regard as finished." Although Sumida is dependent on Michael Howard and Paret's English translation of Clausewitz, and on help from "a native German speaking" graduate assistant trained in military history, he accuses Paret of lacking "complete command" (p. 36) of On War, and of failing to understand "Clausewitz's theoretical intent" (p. 59). Paret's supposed mistake lies in his belief that Clausewitz was engaged in developing "a set of propositions" that "would explain the essential nature of war;" Sumida counters that Clausewitz's "main theoretical concern…is the integrity of the processes of observation and analysis of past military events" (p. 59). Readers who find this distinction opaque are urged to read the rest of the book. This reviewer's understanding of the distinction is that Paret used the opening chapter of On War, entitled "What is War?," as the definitive guide to understanding the rest of the presumably unrevised text.
The third scholar considered in Chapter 2 is W.B. Gallie, a philosopher who first published on Clausewitz in 1978. Gallie dealt with Clausewitz in a single lecture as part of a published series, Philosophers of Peace and War, and he gets gentler treatment than Aron and Paret from Sumida for his praise of Clausewitz's philosophical sophistication and his "high level of suggestive insight" (p. 74), but is also...