Biography of a book: Why Clausewitz’s ‘On War’ still matters
This work by Hew Strachan, a professor at Oxford University and a leading scholar of military history, is a rare phenomenon: A biography of a book, or rather of the classic masterpiece and other writings of Carl von Clausewitz (1780-1831), who served as an officer of middle rank in the Prussian army during the wars of Napoleon.
Clausewitz’s “On War” is widely regarded as the most authoritative analysis of war in any language, and Mr. Strachan provides a thorough evolutionary treatment of it, amply detailing its growth, its several inconsistencies, the formative experience and fierce patriotism of Clausewitz, and his profound chagrin at Prussia’s early failure to resist Napoleon Bonaparte on the battlefield.
Clausewitz was born too late to serve Frederick the Great and too early to serve Bismarck, both of them Prussian masters of controlled war as a finely tuned instrument of policy. But Clausewitz was caught up in the explosion of revolutionary France, which changed the entire nature of war, making it an instrument of a population that had become a zealous mob under arms. The humiliation of Prussia by Napoleon at Jena (1806) left Clausewitz with a profound resentment and sense of shame.
Clausewitz fought at Ligny, three days before Waterloo, when Napoleon broke the Prussians once more. Yet the defeated Prussians regrouped under Gneisenau and Blucher, took the offensive and joined Wellington’s army to inflict not just a defeat, but a total destruction of the French army. From this experience Clausewitz devoted himself to examining the why and how of such reversals of fortune.
Revolution and levees en masse had changed war, as practised by France, from a relatively tidy professional undertaking in which the citizenry was not deeply engaged to a violent reflection of the successful class struggle and its claim on a new order of things in Europe. Both in ferocity and in numbers, Prussia could not match the new, aggressive giant.
Prussia still conducted war as a matter for the ruler and the military. From his experience in this transformation of war, Clausewitz expounded his principle that war cannot succeed unless the government, the military and the population are all committed.
If this principle is to be applied rigorously, the whole idea of a volunteer army works to negate the requirement of popular support, because recruitment of volunteers does not reach sufficiently deeply into the population.
What is gained by the political convenience of a volunteer force and avoidance of a draft is offset by the fact that the bulk of the population has little or no concern for the enterprise. We are seeing this today in the context of Iraq, as growing manpower requirements are met by extensions of deploy- ments and fall heavily on the same, relatively few, people.
Clausewitz found basic fault with the 18th-century concept of strategic maneuver as a means to outwit the enemy, believing that this tradition was a significant cause of Prussia’s defeat in the early campaigns. At the end of the day, he wrote in 1811, “war is nothing but fighting.” Leipzig and Waterloo proved his point.
If a showdown battle is the necessary endgame, the Waterloo allies were fortunate in their commanders. Wellington and Blucher were perfectly typecast to command a showdown battle, yet to complement each other. Blucher: Though aged, he was energetic, impulsive, fearless, motivated by a passionate hatred of the French and a thirst for avenging Jena. Wellington: Cool, astute, ironnerved, seasoned by victories in Portugal and Spain over some of Napoleon’s better marshals (Massena, Victor, Marmont, Junot and Soult), unimpressed by the Bonaparte mystique.
With the United States and Britain involved in a war in Iraq that was conceived in error and in- competently planned, justified and carried out — there could be a valuable role for a book that measured those deficiencies against the principles developed by Clausewitz.
Mr. Strachan’s book, however, is not that book, nor would it be fair to suggest that it should have been. Clausewitz is an old specialty of Mr. Strachan, and he deals with Clausewitz in the context of rather dry scholarship and the testing of intellectual consistency. But it is done with elegance and impressive command of the underlying material.
One cannot help but speculate on what Clausewitz’s thinking might have been, had he been prescient, about two forms of war that preoccupy us today: Terrorism and nuclear war or its threat.
A hint of what he might say about terrorism is provided by his comments about the balance between offense and defense, and his allusion to the role of the Spanish guerillas in resisting Napoleon’s invasion of their country. Clausewitz remarked that the more deeply the offense penetrates enemy territory, the more the balance shifts to defense, as the lines of communication of defense become shorter and those of offense longer, as in the Spanish case.
In Napier’s “History of the Peninsular War” it is reported that Marshal Massena complained that it required a battalion of cavalry to send a dispatch from Spain to Paris. The Spanish guerillas were, of course, terrorists to the French and were treated that way, but that did not alter the basic geometry of Clausewitz’s point.
One may reasonably consider that Clausewitz would view in a similar light the effort of U.S. and allied forces to pursue the guerillas of today — the terrorists — into their own territory in Afghanistan and Iraq where the balance appears to have shifted in favor of the forces with the shorter lines of communication.
As to nuclear war we have no hint of what Clausewitz might have thought. But, as Mr. Strachan points out, Clausewitz did consider the relationship between policy and military action. He sensibly viewed policy — or diplomacy — as the preferred course when no favorable outcome could be predicted from military action.
Clausewitz was a realist and probably would have seen that nuclear, or even conventional, preemption would only work when one party’s attack could eliminate with certainty any possibility of nuclear response. That certainty fades and even disappears as the nuclear facilities on each side multiply. Then carrots, not sticks, become the preferred course.
Clausewitz’s intellectual heirs have a formidable task in putting their minds to work on terrorism and the threat of nuclear war.
David C. Acheson is a retired lawyer and foreign policy analyst and an avid reader of books on the wars of Napoleon.