Carl von Clausewitz concludes his magnum opus with a return to the beginning but from a far larger perspective. While he began Book I asserting that “[w]ar is nothing but a duel on a larger scale,” he begins Book VIII (“War Plans”) by “… deal[ing] with the problem of war as a whole… cover[ing] its dominant, its most important aspect: pure strategy … the central point on which all other threads converge.”
His crescendo is replete with deep historical examples suggesting that Book VIII was probably completed shortly after Books I and II. No mere “outlines” (as we observed in Book VII) are to be found in this final, culminating book. He deftly weaves all of the foundational elements introduced early in this series, sorting and collating across the various sections introduced in the intervening chapters, and now showing us the method behind his dialectic.
In returning to his abstract notion of “absolute war”, indivisible in nature and simultaneous in time, he underscores the importance of “…develop[ing] our concept of war as it ought to be fought.” He offers insights into scaling the fighting force for the level of effort expected (an idea contrary to the modern inclination for massive overmatch within our Leviathan), and even offers a chapter on the seemingly counter-intuitive idea of “limited aims”.
But Clausewitz’s most important insights are his Chapter Six deep dive into the most-quoted (and, perhaps, least understood) dictum: that “war is a continuation of politics by other means.” The first part of Chapter Six describes the effect of politics (and political aim) on the military campaign, and the utter importance of “incentive”: “…[A]ll stagnate for lack of real incentive.” Part B continues to underscore the political nature of war, and that war is simply one additional facet of the overarching political and diplomatic dialog: “This unity lies in the concept that war is only a branch of political activitity; that it is in no sense autonomous.”
In his heart, Clausewitz is the ultimate pragmatist. He eschews the complex machinations of Jomini’s concept of “methodical battle”, instead favoring the direct approach: closing with and engaging the enemy. And while On War is rich in theoretical constructs, Clausewitz does little to mask his animosity toward the theoretician removed from reality: “… [T]he man who sacrifices the possible in search of the impossible is a fool.” With that sentence, Carl von Clausewitz concludes the most monumental book on the nature of war and warfighting a book that has shaped Western militaries and thinking on national security for nearly two centuries.