The Hierarchy of Combat

The second conceptual element in Trevor Dupuy’s theory of combat is his definition of the hierarchy of combat:

[F]ghting between armed forces—while always having the characteristics noted [in the definition of military combat], such as fear and planned violence—manifests itself in different fashions from different perspectives. In commonly accepted military terminology, there is a hierarchy of military combat, with war as its highest level, followed by campaign, battle, engagement, action, and duel.

A war is an armed conflict, or a state of belligerence, involving military combat between two factions, states, nations, or coalitions. Hostilities between the opponents may be initiated with or without a formal declaration by one or both parties that a state of war exists. A war is fought for particular political or economic purposes or reasons, or to resist an enemy’s efforts to impose domination. A war can be short, sometimes lasting a few days, but usually is lengthy, lasting for months, years, or even generations.

A campaign is a phase of a war involving a series of operations related in time and space and aimed toward achieving a single, specific, strategic objective or result in the war. A campaign may include a single battle, but more often it comprises a number of battles over a protracted period of time or a considerable distance, but within a single theater of operations or delimited area. A campaign may last only a few weeks, but usually lasts several months or even a year.

A battle is combat between major forces, each having opposing assigned or perceived operational missions, in which each side seeks to impose its will on the opponent by accomplishing its own mission, while preventing the opponent from achieving his. A battle starts when one side initiates mission-directed combat and ends when one side accomplishes its mission or when one or both sides fail to accomplish the mission(s). Battles are often parts of campaigns. Battles between large forces usually are made up of several engagements, and can last from a few days to several weeks. Naval battles tend to be short and—in modern times—decisive.

An engagement is combat between two forces, neither larger than a division nor smaller than a company, in which each has an assigned or perceived mission. An engagement begins when the attacking force initiates combat in pursuit of its mission and ends when the attacker has accomplished the mission, or ceases to try to accomplish the mission, or when one or both sides receive significant reinforcements, thus initiating a new engagement. An engagement is often part of a battle. An engagement normally lasts one or two days; it may be as brief as a few hours and is rarely longer than five days.

An action is combat between two forces, neither larger than a battalion nor smaller than a squad, in which each side has a tactical objective. An action begins when the attacking force initiates combat to gain its objective, and ends when the attacker wins the objective, or one or both forces withdraw, or both forces terminate combat. An action often is part of an engagement and sometimes is part of a battle. An action lasts for a few minutes or a few hours and never lasts more than one day.

A duel is combat between two individuals or between two mobile fighting machines, such as combat vehicles, combat helicopters, or combat aircraft, or between a mobile fighting machine and a counter-weapon. A duel begins when one side opens fire and ends when one side or both are unable to continue firing, or stop firing voluntarily. A duel is almost always part of an action. A duel lasts only a few minutes. [Dupuy, Understanding War, 64-66]

Trevor Dupuy’s Definition of Military Combat

Ernst Zimmer: “Das Lauenburgische Jäger-Bataillon Nr. 9 bei Gravelotte” [Wikipedia]

The first element in Trevor Dupuy’s theory of combat is his definition of military combat:

I define military combat as a violent, planned form of physical interaction (fighting) between two hostile opponents, where at least one party is an organized force, recognized by governmental or de facto authority, and one or both opposing parties hold one or more of the follow-on objectives: to seize control of territory or people; to prevent the opponent from seizing or controlling territory or people; to protect one’s own territory or people; to dominate, destroy, or incapacitate the opponent.

The impact of weapons creates an environment of lethality, danger, and fear in which achievement of the objectives by one party may require the opponent to choose among: continued resistance and resultant destruction; retreat and loss of territory, facilities, and people; surrender. Military combat begins in any interaction, or at any level of combat from duel to full-scale war, when weapons are first employed with hostile intent by one or both opponents.  Military combat ends for any interaction or level of combat when both sides have stopped fighting.

There are two key points in this definition that I wish to emphasize. Though there may be much in common between military combat and a brawl in a barroom, there are important differences. The opponents in military combat are to some degree organized, and both represent a government or quasi-governmental authority. There is one other essential difference: the all-pervasive influence of fear in a lethal environment. People have been killed in barroom brawls, but this is exceptional. In military combat there is the constant danger of death from lethal weapons employed by opponents with deadly intent. Fear is without question the most important characteristic of combat. [Dupuy, Understanding War, 63-64]

The Elements of Trevor Dupuy’s Theory of Combat

Trevor Dupuy’s combat models (the Quantified Judgement Model (QJM) and the Tactical Numerical Deterministic Model (TNDM)) are formal expressions of his theory of combat. Dupuy provided an extensive discussion of the basis for his theory in his books, particularly Understanding Combat: History and Theory of Combat (NOVA Publications, 1987). While many are familiar with his models, fewer are aware of the concepts that he based it upon. This will be the first in a series of posts looking at those elements.

As Dupuy explained,

As a starting point for an explanation of a scientific theory, it is useful to define fundamental terms, to state and explain critical assumptions, and to establish—or limit—the scope of the discussion that follows. The definitions and explanations that follow are generally consistent with usage in the military and analytical communities, and with definitions that have been formulated for its work by The Military Conflict Institute. However, I have in some instances modified or restated these to conform to my own ideas and usage. [Dupuy, Understanding Combat, 63]

The basic elements of his theory of combat are:

Definition of Military Combat
The Hierarchy of Combat
The Conceptual Components of Combat
The Scope of Theory
Definition of a Theory of Combat

These will each be discussed in future posts.

Dupuy’s Verities: The Complexities of Combat

“The Battle of Leipzig, 16-19 October 1813” by A.I. Zauerweid (1783-1844) [Wikimedia]

The thirteenth and last of Trevor Dupuy’s Timeless Verities of Combat is:

Combat is too complex to be described in a single, simple aphorism.

From Understanding War (1987):

This is amply demonstrated by the preceding [verities]. All writers on military affairs (including this one) need periodically to remind themselves of this. In military analysis it is often necessary to focus on some particular aspect of combat. However, the results of such closely focused analyses must the be evaluated in the context of the brutal, multifarious, overlapping realities of war.

Trevor Dupuy was sometimes accused of attempting to reduce war to a mathematical equation. A casual reading of his writings might give that impression, but anyone who honestly engages with his ideas quickly finds this to be an erroneous conclusion. Yet, Dupuy believed the temptation to simplify and abstract combat and warfare to be common enough that he he embedded a warning against doing so into his basic theory on the subject. He firmly believed that human behavior comprises the most important aspect of combat, yet it is all too easy to miss the human experience of war figuring who lost or won and why, and counts of weapons, people, and casualties. As a military historian, he was keenly aware that the human stories behind the numbers—however imperfectly recorded and told—tell us more about the reality of war than mere numbers on their own ever will.

Dupuy’s Verities: Combat Power =/= Firepower

A U.S. 11th Marines 75mm pack howitzer and crew on Guadalcanal, September or October, 1942. The lean condition of the crewmembers indicate that they haven’t been getting enough nutrition during this period. [Wikipedia]

The ninth of Trevor Dupuy’s Timeless Verities of Combat is:

Superior Combat Power Always Wins.

From Understanding War (1987):

Military history demonstrates that whenever an outnumbered force was successful, its combat power was greater than that of the loser. All other things being equal, God has always been on the side of the heaviest battalions and always will be.

In recent years two or three surveys of modern historical experience have led to the finding that relative strength is not a conclusive factor in battle outcome. As we have seen, a superficial analysis of historical combat could support this conclusion. There are a number of examples of battles won by the side with inferior numbers. In many battles, outnumbered attackers were successful.

These examples are not meaningful, however, until the comparison includes the circumstances of the battles and opposing forces. If one take into consideration surprise (when present), relative combat effectiveness of the opponents, terrain features, and the advantage of defensive posture, the result may be different. When all of the circumstances are quantified and applied to the numbers of troops and weapons, the side with the greater combat power on the battlefield is always seen to prevail.

The concept of combat power is foundational to Dupuy’s theory of combat. He did not originate it; the notion that battle encompasses something more than just “physics-based” aspects likely originated with British theorist J.F.C. Fuller during World War I and migrated into U.S. Army thinking via post-war doctrinal revision. Dupuy refined and sharpened the Army’s vague conceptualization of it in the first iterations of his Quantified Judgement Model (QJM) developed in the 1970s.

Dupuy initially defined his idea of combat power in formal terms, as an equation in the QJM:

P = (S x V x CEV)


P = Combat Power
S = Force Strength
V = Environmental and Operational Variable Factors
CEV = Combat Effectiveness Value

Essentially, combat power is the product of:

  • force strength as measured in his models through the Theoretical/Operational Lethality Index (TLI/OLI), a firepower scoring method for comparing the lethality of weapons relative to each other;
  • the intangible environmental and operational variables that affect each circumstance of combat; and
  • the intangible human behavioral (or moral) factors that determine the fighting quality of a combat force.

Dupuy’s theory of combat power and its functional realization in his models have two virtues. First, unlike most existing combat models, it incorporates the effects of those intangible factors unique to each engagement or battle that influence combat outcomes, but are not readily measured in physical terms. As Dupuy argued, combat consists of more than duels between weapons systems. A list of those factors can be found below.

Second, the analytical research in real-world combat data done by him and his colleagues allowed him to begin establishing the specific nature combat processes and their interaction that are only abstracted in other combat theories and models. Those factors and processes for which he had developed a quantification hypothesis are denoted by an asterisk below.

Dupuy’s Verities: The Inefficiency of Combat

The “Mud March” of the Union Army of the Potomac, January 1863.

The twelfth of Trevor Dupuy’s Timeless Verities of Combat is:

Combat activities are always slower, less productive, and less efficient than anticipated.

From Understanding War (1987):

This is the phenomenon that Clausewitz called “friction in war.” Friction is largely due to the disruptive, suppressive, and dispersal effects of firepower upon an aggregation of people. This pace of actual combat operations will be much slower than the progress of field tests and training exercises, even highly realistic ones. Tests and exercises are not truly realistic portrayals of combat, because they lack the element of fear in a lethal environment, present only in real combat. Allowances must be made in planning and execution for the effects of friction, including mistakes, breakdowns, and confusion.

While Clausewitz asserted that the effects of friction on the battlefield could not be measured because they were largely due to chance, Dupuy believed that its influence could, in fact, be gauged and quantified. He identified at least two distinct combat phenomena he thought reflected measurable effects of friction: the differences in casualty rates between large and small sized forces, and diminishing returns from adding extra combat power beyond a certain point in battle. He also believed much more research would be necessary to fully understand and account for this.

Dupuy was skeptical of the accuracy of combat models that failed to account for this interaction between operational and human factors on the battlefield. He was particularly doubtful about approaches that started by calculating the outcomes of combat between individual small-sized units or weapons platforms based on the Lanchester equations or “physics-based” estimates, then used these as inputs for brigade and division-level-battles, the results of which in turn were used as the basis for determining the consequences of theater-level campaigns. He thought that such models, known as “bottom up,” hierarchical, or aggregated concepts (and the prevailing approach to campaign combat modeling in the U.S.), would be incapable of accurately capturing and simulating the effects of friction.

Dupuy’s Verities: The Effects of Firepower in Combat

A German artillery barrage falling on Allied trenches, probably during the Second Battle of Ypres in 1915, during the First World War. [Wikimedia]

The eleventh of Trevor Dupuy’s Timeless Verities of Combat is:

Firepower kills, disrupts, suppresses, and causes dispersion.

From Understanding War (1987):

It is doubtful if any of the people who are today writing on the effect of technology on warfare would consciously disagree with this statement. Yet, many of them tend to ignore the impact of firepower on dispersion, and as a consequence they have come to believe that the more lethal the firepower, the more deaths, disruption, and suppression it will cause. In fact, as weapons have become more lethal intrinsically, their casualty-causing capability has either declined or remained about the same because of greater dispersion of targets. Personnel and tank loss rates of the 1973 Arab-Israeli War, for example, were quite similar to those of intensive battles of World War II and the casualty rates in both of these wars were less than in World War I. (p. 7)

Research and analysis of real-world historical combat data by Dupuy and TDI has identified at least four distinct combat effects of firepower: infliction of casualties (lethality), disruption, suppression, and dispersion. All of them were found to be heavily influenced—if not determined—by moral (human) factors.

Again, I have written extensively on this blog about Dupuy’s theory about the historical relationship between weapon lethality, dispersion on the battlefield, and historical decline in average daily combat casualty rates. TDI President Chris Lawrence has done further work on the subject as well.

TDI Friday Read: Lethality, Dispersion, And Mass On Future Battlefields

Human Factors In Warfare: Dispersion

Human Factors In Warfare: Suppression

There appears to be a fundamental difference in interpretation of the combat effects of firepower between Dupuy’s emphasis on the primacy of human factors and Defense Department models that account only for the “physics-based” casualty-inflicting capabilities of weapons systems. While U.S. Army combat doctrine accounts for the interaction of firepower and human behavior on the battlefield, it has no clear method for assessing or even fully identifying the effects of such factors on combat outcomes.

A Comment On The Importance Of Reserves In Combat

An German Army A7V near the Somme on March 26, 1918 [] Operation Michael was the first of a series of German Army offensives on the Western Front in the spring of 1918. In late March, 74 German divisions employing infiltration tactics created a breach in a sector of the line held by the British Army. The Germans advanced up to 40 miles and captured over 75,000 British soldiers, but the ability of the British and French to redeploy reserves via rail halted the offensive in early April short of strategic success.

In response to my previous post on Trevor Dupuy’s verity regarding the importance of depth and reserves for successful defense, a commenter posed the following question: “Is the importance of reserves mainly in its own right, or to mitigate the advantages of attacker surprise?”

The importance of reserves to both attacker and defender is as a hedge against the circumstantial uncertainties of combat. Reserves allow attacking and defending commanders the chance to maintain or regain initiative in response to the outcomes of battle. The side that commits its last reserves before its opponent does concedes the initiative to the enemy, probably irrevocably.

In Trevor Dupuy’s theory of combat, the intrinsic superiority of the defensive posture (as per Clausewitz) is the corollary to the attacker’s inherent advantage in initiative. When combined with the combat multipliers of favorable terrain and prepared positions or fortifications, the combat power of a defending force is greatly enhanced. This permits a defending commander to reap the benefit of economy of force to create reserves. When arrayed in sufficient depth to prevent an attacker from engaging them, reserves grant flexibility of response to the defender. A linear defense or improperly placed reserves concede this benefit to the attacker at the outset, permitting the attacking commander to exploit initiative to mass superior combat power at a decisive point without reserves to interfere.

A defender’s reserves are certainly useful in mitigating attacker surprise, but in Dupuy’s theories and models, surprise is a combat multiplier available to both attacker and defender. As perhaps the most powerful combat multiplier available on the battlefield, surprise in the form of a well-timed counterattack by a defender can devastate an attacking force. Even an unexpected tactical wrinkle by a defender can yield effective surprise.

Dupuy’s Verities: The Requirements For Successful Defense

A Sherman tank of the U.S. Army 9th Armored Division heads into action against the advancing Germans during the Battle of the Bulge. {Warfare History Network]

The eighth of Trevor Dupuy’s Timeless Verities of Combat is:

Successful defense requires depth and reserves.

From Understanding War (1987):

Successful defense requires depth and reserves. It has been asserted that outnumbered military forces cannot afford to withhold valuable firepower from ongoing defensive operations and keep it idle in reserve posture. History demonstrates that this is specious logic, and that linear defense is disastrously vulnerable. Napoleon’s crossing of the Po in his first campaign in 1796 is perhaps the classic demonstration of the fallacy of linear (or cordon) defense.

The defender may have all of his firepower committed to the anticipated operational area, but the attacker’s advantage in having the initiative can always render much of that defensive firepower useless. Anyone who suggests that modern technology will facilitate the shifting of engaged firepower in battle overlooks three considerations: (a) the attacker can inhibit or prevent such movement by both direct and indirect means, (b) a defender engaged in a fruitless firefight against limited attacks by numerically inferior attackers is neither physically nor psychologically attuned to making lateral movements even if the enemy does not prevent or inhibit it, and (c) withdrawal of forces from the line (even if possible) provides an alert attacker with an opportunity for shifting the thrust of his offensive to the newly created gap in the defenses.

Napoleon recognized that hard-fought combat is usually won by the side committing the last reserves. Marengo, Borodino, and Ligny are typical examples of Napoleonic victories that demonstrated the importance of having resources available to tip the scales. His two greatest defeats, Leipzig and Waterloo, were suffered because his enemies still had reserves after his were all committed. The importance of committing the last reserves was demonstrated with particular poignancy at Antietam in the American Civil War. In World War II there is no better example than that of Kursk. [pp. 5-6]

Dupuy’s observations about the need for depth and reserves for a successful defense take on even greater current salience in light of the probably character of the near-future battlefield. Terrain lost by an unsuccessful defense may be extremely difficult to regain under prevailing circumstances.

The interaction of increasing weapon lethality and the operational and human circumstantial variables of combat continue to drive the long-term trend in dispersion of combat forces in frontage and depth.

Long-range precision firepower, ubiquitous battlefield reconnaissance and surveillance, and the effectiveness of cyber and information operations will make massing of forces and operational maneuver risky affairs.

As during the Cold War, the stability of alliances may depend on a willingness to defend forward in the teeth of effective anti-access/area denial (A2/AD) regimes that will make the strategic and operational deployment of reserves risky as well. The successful suppression of A2/AD networks might court a nuclear response, however.

Finding an effective solution for enabling a successful defense-in-depth in the future will be a task of great difficulty.

Dupuy’s Verities: The Advantage Of The Offensive

Union assault on the “Mule Shoe” salient, 12 May 1864, by Thure de Thulstrup (1887) [Wikimedia]

The seventh of Trevor Dupuy’s Timeless Verities of Combat is:

An attacker willing to pay the price can always penetrate the strongest defenses.

From Understanding War (1987):

No matter how alert the defender, no matter how skillful his dispositions to avoid or mitigate the effects of surprise or the effects of flank or rear attack, a skillful attacker can always achieve at least a temporary advantage for some time at a place he has selected. This is one reason why Napoleon always endeavored to seize and retain the initiative. In the great battles of 1864 and 1865 in Virginia, Lee was always able to exploit his defensive advantage to the utmost. But Grant equally was always able to achieve a temporary superiority when and where he wished. This did not always result in a Union victory—given Lee’s defensive skill—but invariably it forced Lee to retreat until he could again impose a temporary stalemate with the assistance of powerful field fortifications. A modern example can be found in the Soviet offensive relieving Leningrad in 1943. Another was the Allied break-out from the Normandy beachhead in July and August of 1944.

The exact meaning of this verity is tricky to determine, as the phrase “willing to pay the price” does a lot of work here. History is certainly replete with examples of Phyrric victories, where the cost paid for battlefield success deprived the attacker of any clear benefit. (The U.S. Civil War Battle of Chickamauga in 1863 would be an example in line with Dupuy’s description above.) Perhaps “willing and able to pay the price” would have been a better of way stating this. And, of course, no attack is guaranteed to succeed.

What Dupuy had in mind here is probably best understood in the context of two other of his verities “Offensive action is essential to positive combat results” and “Initiative permits application of preponderant combat power.” Even if the defensive may be the stronger form of combat, the offensive affords certain inherent potential advantages that can enable attackers to defeat the strongest of defenses if conducted effectively, sufficiently resourced, and determinedly pressed.