A few months ago I read Carl von Clausewitz’s monumental On War.  A commander I trust told me as a young lieutenant not to bother with it until after company command; I cheated by a few weeks.  I’m writing this to put down my own thoughts while they’re still fresh, while reserving any criticism for a later post (here, and then what I think he’s right about).  Anyone seriously interested in a synopsis of Clausewitz should probably consult Bernard Brodie’s 1976 commentary rather than my own scribbling.

I read the 1976 indexed edition translated by Michael Howard and Peter Paret, published by Princeton University Press in 1984.  The translators favored clarity over transliteration, e.g. rendering several words and expression as “moral”.  I have no interest in textual analysis of a lengthy 19th-century German work and will not comment further on this.

Eight books comprise On War, with evidence that Clausewitz intended to write at least one other.  He had begun the process of organizing and editing beginning with Book One when he died; in a preface written shortly before his death he claims to be completely satisfied only with Book One, Chapter One.  Several parts of On War are obviously unfinished, with for instance Book 7, Chapter 21 “Invasion” consisting of a brief summary for later expansion.  Clausewitz clearly intended to become more prescriptive at the end of his masterpiece; even unfinished, it’s obvious that his descriptions of the nature and conduct of war would culminate in explicit although characteristically qualified prescriptions for the planning and conduct of war, beginning with Book 8, “War Plans”.  A clear contradiction exists between Clausewitz’s earlier ideas on the value of the decisive battle and his later, post-1812 experience.  Despite its incomplete state, however, I was struck by the level of insight.  Even when Clausewitz drifts from timeless advice, he has much to offer anyone interested in military history.  I did deliberately omit any comments on portions of this work that I felt were too bound-up in contemporary concerns.

While Clausewitz strives for timelessness and often achieves it, he can’t help but occasionally enter the mire of tactical discussion.  Clausewitz recognizes that the scope of his subject demands nuance, and he rarely makes unqualified statements.  He also generally limits himself to description rather than prescription.

The Nature of War

On the first page, Clausewitz defines war as “an act of force to compel the enemy to do our will”.  Before that, however, he writes in the 1827 preface his famous maxim that “war is nothing but the continuation of policy by other means”.  (I will leave aside any quibbling over German words here, but will note that another widely used translation renders “policy” here as “politics”.)  This is a descriptive statement.  Clausewitz isn’t saying that war ought to be a continuation of politics, or that war aims and policy aims will be most effective if they are somehow “aligned”.  He doesn’t mean that politics shouldn’t “get in the way” of war or vice versa.  He means exactly what that says: that war is an extension or manifestation of politics, i.e. of human interaction as it relates to the behavior of states and societies.

The context and importance of this statement has to do with two concepts: “absolute” and “real” war.  “Absolute war” might be called “Ideal War”, as in Plato’s Ideal.  Fighting tends to escalate because the fighters want to win and don’t want to lose.  Also, because the pace of fighting is dictated by the enemy (for both sides!) the escalation of effort is somewhat outside of the control of either party.  If the enemy escalates, I have to match or exceed his strength; the process continues for the other side in a spiral. As a result, nations at war commit more and more resources to fighting until eventually everything – whatever that means; people, materials, willpower – is devoted to the fight.  Clausewitz goes a little further and says that maximum effort will tend to require concentration in time.  An “Absolute War”, then, consists of every physical, mental, and spiritual resource a nation can summon exerted all at once to completely prostrate (or not) an enemy who responds in kind.

Obviously, this never actually happens.  Most wars are fought with half-measures or for limited objectives.  Even though some wars, like Napoleon’s conquests, are more absolute than others, they still don’t involve literally the entire possible output of the nation.  (If you’re thinking of World War Two here, two words: chemical weapons.  We can explore this in a later post.)  Therefore, there must be countervailing tendencies to the spiral of violence.  The interaction between ABSOLUTE WAR and these other factors form a dialectic (Clausewitz does not use this term) whose synthesis is Actual War.  Some of these mitigating factors include the laws of physics, differences in character of key individuals, the details of national political systems, custom & habit, the expected effects of victory or defeat, the “friction” involved in the coordination of warfighting forces, and incomplete information (the “fog of war”).  In short, while war does have an escalating tendency, which has its own propelling logic, other factors work to produce the non-total wars seen in the real world.  Even in apparently “absolute” wars these factors still act to restrain the combatants from the ideal purity of total effort.  As a corollary, wars don’t generally result in the total defeat and unconditional surrender – much less the annihilation – of one side.  Napoleon’s attempt to impose such a state on the Russians was an anomaly – and a failure.

All military operations, because of their complexity, are subject to “friction”.  “Everything in war is simple; but in war, simple things are very difficult.”  Also, the burdens of command – especially the knowledge of his responsibility for the death and suffering of those in his army – will spiritually destroy the average person.  Thus great commanders tend to be exceptional individuals.  He must be above all be bold, determined, and courageous.  However, he must also possess a formidable intellect as well as an active imagination.  The latter enables a “sense of locality” enabling him to “quickly and accurately grasp the topography of any area”.  These characteristics must be present in the correct quantities – for instance, boldness or determination unrestrained by intellect may become rashness or obstinacy.  The need for genius is particularly important for the commander-in-chief, who exists on a separate level even from his immediate subordinate generals.  Clausewitz doesn’t attempt to devise a definitive rule for these qualities, and comments elsewhere suggests they depend on the circumstances anyway. Demands decrease as one descends the ranks; this means that exceptional feats are more common at lower ranks and that most outstanding junior officers aren’t actually suited to supreme command.  Fortunately, however, even middling leaders – perhaps one who is courageous and has good sense but is not particularly bright or imaginative – can serve even in very high positions under a properly qualified supreme commander.

One area in which boldness and determination in a commander take on an oversize significance is after a victory.  The efficacy of pursuit accounts for most of the real strategic effect (not Clausewitz’s term!) of a victory. Sometimes an effective pursuit isn’t possible either because of geography, visibility, or the exhaustion of soldiers (whom combat “burns to cinders” psychologically), but other times it is.  To recognize such an opportunity and capitalize on it makes the difference in how much value a commander can extract from a given victory.  Conversely, rear guard actions ensure a defeated general minimizes the effects of his defeat.

Armies have both moral and physical qualities which together comprise their total strength.  Of the physical factors, number is one of the most important assuming some basic level of competence.  Even the greatest commanders have difficulty overcoming 2:1 superiority in warfare.  Geometry also plays a role; while forces generally should concentrate rather than divide, Clausewitz advocates a “concentric attack” as the most advantageous form of the offensive.  I believe a better term for this is “concave” (as opposed to linear) attack given his use of Waterloo as an example – an attack should come from multiple directions when this can be done without risking defeat in detail by a defending force operating on interior lines, and a concave-shaped front allows this.  Either way, an attack from multiple directions.

The different branches of an army – infantry, cavalry, and artillery – have different qualities physically.  While the most powerful armies combine all three branches, infantry are the most indispensable and cavalry the most dispensable.  Artillery is the most destructive branch and by nature may be used to make up relative deficits in population of men and horses by small, wealthy states.

“Patriotic spirit” constitutes another moral virtue, one which is particularly important in types of warfare fought with minimal supervision of individual soldiers and small units such as mountain warfare or in popular insurgencies.  The best regular armies possess a “military virtue” that develops exclusively from fighting and, especially, winning battles and campaigns.  The “military virtue” produced by peacetime drill of a regular force is only a cheap imitation of the real item, although “frequent exertions of the army to the utmost limits of its strength” produces an acceptable substitute.  At any rate, the capabilities of “regular” or “professional” soldiers without combat experience may in fact be relatively underwhelming despite their daily drills and discipline.

Controversially, Clausewitz asserts that defense is the stronger form of war.  On this subject, Clausewitz makes many qualifying statements that boil down to: to invade is more difficult than to defend from invasion.  Counterattacking, for instance, is a critical component of an effective defense.  This is partly because friction in war simply favors staying put or awaiting an enemy, and awaiting the enemy is the essence of the defense.  Also, invaders face more difficulty than defenders because the unfriendliness or uncooperativeness of the local population, unfamiliarity with the land, and the length and latency of supply lines increases friction.  Sometimes these factors may be less troublesome than others but they are always present.  In the worse circumstances, invading armies may face a popular insurrection that rapidly diverts resources away from their main effort in defeating an enemy army.

These factors also mean that offensive capability is a consumable resource.  Nations gather it, and when they employ this capability in expeditionary warfare, it dwindles over time until the attacking force is weaker than the defender.  Why, then, would any nations ever fight offensively?  To “buy” concessions from the defender.  The nature of the concessions sought is a matter of policy.

The Center of Gravity

The concept of the Center of Gravity has assumed significant importance in the language of strategy since Clausewitz’s day.  A Center of Gravity is, in Clausewitz’s words, “[T]he hub of all power and movement, on which everything depends. That is the point against which all our energies should be directed”.  (He does not give this definition until Book 8 and I don’t know if I would have seized upon it as significant without prior knowledge of the term.)  To defeat the enemy, one must focus one’s resources on the center(s) of gravity and overcome it.  Ideally, a nation at war might only have one center of gravity but in reality there may be several.  The existence of alliances and coalitions tends to make for larger numbers of centers of gravity.  This is not just because of the multiple interests involved but also because the relationships between the allied nations constitutes its own center.

Clausewitz thus advocates meeting strength with strength as a way to victory, although he acknowledges that this will not always be possible for reasons corresponding to the usual factors working against prosecution of an absolute war.

Victory in Battle

He downplays the effects of surprise at the strategic/operational level while acknowledging its usefulness tactically (organizing an invasion in secret is too difficult to conceal, and it’s not possible to overwhelm the enemy fast enough anyway) or of “cunning” and “deception” in general.  Essentially, he argues that the opportunity cost of these is too high.  In order to make a demonstration or feint effective, a commander must allocate too many resources that could instead be used to simply crush the enemy.  Similar logic lies behind Clausewitz’s warning against relying too heavily on either harassing or “cutting off” lines of communication; it is difficult to inflict serious damage this way, the damage inflicted takes some time to tell on the enemy even if significant, when a commander uses significant forces to cut off communication he risks exposing his own communication to similar efforts by the enemy.  This may not actually result in a net zero effort, but only in exceptional circumstances will the effects be remarkable.  On the other hand, peasant partisans and other irregular forces can do this to increase friction on the attacking enemy without much negative effect on military power.

Decisive victory in battle is the most important goal for a commander not only because of its “absolute war” effect of disarming the enemy, but also because of it improves the position of one’s country during peace negotiations.  Supply line harassment, maneuvering enemies out of unfavorable positions, living off the land at the enemy’s expense, besieging and capturing fortresses: all of these are good, but ultimately “small change” compared to the “gold and silver” of victory in battle.  An occupied province and a decisive victory gets you a lot further at peace negotiations than an occupied province.

Victory also acts as a sort of universal solvent; once a general and his army have accomplished it, small problems tend to melt away.  Supply, billeting, relations with occupied populations, friction in general – all of these complex factors simply recede after a decisive victory.   Clausewitz’s definition of victory here is a tad circular: how does one know if he has achieved a decisive victory?  Because he no longer has these small problems.  And he has these small problems because he hasn’t achieved a decisive victory.

Of course, since such a victory is so valuable, a general should make sure conditions are set for it to take place.  Generally, an invader should try to force a decision immediately.  A defender should delay battle until he can win – allowing the invader to fritter away his offensive resources in simply existing away from his base – but cannot do this indefinitely because of the real moral and physical damage caused by such a strategy.

In the last book, “War Plans”, Clausewitz ends by recommending that major invasions take the form of independent but ultimately converging armies, acting with the greatest speed possible.   He uses a hypothetical invasion of France by a British-Continental alliance as an example.  The book clearly presages the Schlieffen plan developed by the German General Staff a generation later.