Tag Combat Power

Human Factors In Warfare: Combat Intensity

Battle of Spotsylvania by Thure de Thulstrup (1886) [Library of Congress]

Trevor Dupuy considered intensity to be another combat phenomena influenced by human factors. The variation in the intensity of combat is an aspect of battle that is widely acknowledged but little studied.

No one who has paid any attention at all to historical combat statistics can have failed to notice that some battles have been very bloody and hard-fought, while others—often under circumstances superficially similar—have reached a conclusion with relatively light casualties on one or both sides. I don’t believe that it is terribly important to find a quantitative reason for such differences, mainly because I don’t think there is any quantitative reason. The differences are usually due to such things as the general circumstances existing when the battles are fought, the personalities of the commanders, and the natures of the missions or objectives of one or both of the hostile forces, and the interactions of these personalities and missions.

From my standpoint the principal reason for trying to quantify the intensity of a battle is for purposes of comparative analysis. Just because casualties are relatively low on one or both sides does not necessarily mean that the battle was not intensive. And if the casualty rates are misinterpreted, then the analysis of the outcome can be distorted. For instance, a battle fought on a flat plain between two military forces will almost invariably have higher casualty rates for both sides than will a battle between those same two forces in mountainous terrain. A battle between those two forces in a heavy downpour, or in cold, wintry weather, will have lower casualties than when the forces are opposed to each other, under otherwise identical circumstances, in good weather. Casualty rates for small forces in a given set of circumstances are invariably higher than the rates for larger forces under otherwise identical circumstances.

If all of these things are taken into consideration, then it is possible to assess combat intensity fairly consistently. The formula I use is as follows:

CI = CR / (sz’ x rc x hc)

When:     CI = Combat Intensity Measure

CR = Casualty rate in percent per day

sz’ = Square root of sz, a factor reflecting the effect of size upon casualty rates, derived from historical experience

rc = The effect of terrain on casualty rates, derived from historical experience

hc = The effect of weather on casualty rates, derived from historical experience

I then (somewhat arbitrarily) identify seven levels of intensity:

0.00 to 0.49 Very low intensity (1)

0.50 to 0.99 Low intensity (56)

1.00 to 1.99 Normal intensity (213)

2.00 to 2.99 High intensity (101)

3.00 to 3.99 Very high intensity (30)

4.00 to 5.00 Extremely high intensity (17)

Over 5.00 Catastrophic outcome (20)

The numbers in parentheses show the distribution of intensity on each side in 219 battles in DMSi’s QJM data base. The catastrophic battles include: the Russians in the Battles of Tannenberg and Gorlice Tarnow on the Eastern Front in World War I; the Russians on the first day of the Battle of Kursk in July 1943; a British defeat in Malaya in December, 1941; and 16 Japanese defeats on Okinawa. Each of these catastrophic instances, quantitatively identified, is consistent with a qualitative assessment of the outcome.

[UPDATE]

As Clinton Reilly pointed out in the comments, this works better when the equation variables are provided. These are from Trevor N. Dupuy, Attrition Forecasting Battle Casualties and Equipment Losses in Modern War (Fall Church, VA: NOVA Publications, 1995), pp. 146, 147, 149.

Human Factors In Warfare: Surprise

By John Trumbull (1756-1843) – Yale University Art Gallery – The Death of Paulus Aemilius at the Battle of Cannae, Public Domain

Trevor Dupuy considered surprise to be one of the most important human factors on the battlefield.

A military force that is surprised is severely disrupted, and its fighting capability is severely degraded. Surprise is usually achieved by the side that has the initiative, and that is attacking. However, it can be achieved by a defending force. The most common example of defensive surprise is the ambush.

Perhaps the best example of surprise achieved by a defender was that which Hannibal gained over the Romans at the Battle of Cannae, 216 BC, in which the Romans were surprised by the unexpected defensive maneuver of the Carthaginians. This permitted the outnumbered force, aided by the multiplying effect of surprise, to achieve a double envelopment of their numerically stronger force.

It has been hypothesized, and the hypothesis rather conclusively substantiated, that surprise can be quantified in terms of the enhanced mobility (quantifiable) which surprise provides to the surprising force, by the reduced vulnerability (quantifiable) of the surpriser, and the increased vulnerability (quantifiable) of the side that is surprised.

I have written in detail previously about Dupuy’s treatment of surprise. He cited it as one of his timeless verities of combat.  As one of the most powerful force multipliers available in battle, he calculated that achieving complete surprise could more than double the combat power of a force.

Human Factors In Warfare: Defensive Posture

U.S. Army troops shelter in defensive trenches at the Battle of Anzio, Italy, 1944. [U.S. Army Center for Military History]

Like dispersion on the battlefield, Trevor Dupuy believed that fighting on the defensive derived from the effects of the human element in combat.

When men believe that their chances of survival in a combat situation become less than some value (which is probably quantifiable, and is unquestionably related to a strength ratio or a power ratio), they cannot and will not advance. They take cover so as to obtain some protection, and by so doing they redress the strength or power imbalance. A force with strength y (a strength less than opponent’s strength x) has its strength multiplied by the effect of defensive posture (let’s give it the symbol p) to a greater power value, so that power py approaches, equals, or exceeds x, the unenhanced power value of the force with the greater strength x. It was because of this that [Carl von] Clausewitz–who considered that battle outcome was the result of a mathematical equation[1]–wrote that “defense is a stronger form of fighting than attack.”[2] There is no question that he considered that defensive posture was a combat multiplier in this equation. It is obvious that the phenomenon of the strengthening effect of defensive posture is a combination of physical and human factors.

Dupuy elaborated on his understanding of Clausewitz’s comparison of the impact of the defensive and offensive posture in combat in his book Understanding War.

The statement [that the defensive is the stronger form of combat] implies a comparison of relative strength. It is essentially scalar and thus ultimately quantitative. Clausewitz did not attempt to define the scale of his comparison. However, by following his conceptual approach it is possible to establish quantities for this comparison. Depending upon the extent to which the defender has had the time and capability to prepare for defensive combat, and depending also upon such considerations as the nature of the terrain which he is able to utilize for defense, my research tells me that the comparative strength of defense to offense can range from a factor with a minimum value of about 1.3 to maximum value of more than 3.0.[3]

NOTES

[1] Dupuy believed Clausewitz articulated a fundamental law for combat theory, which Dupuy termed the “Law of Numbers.” One should bear in mind this concept of a theory of combat is something different than a fundamental law of war or warfare. Dupuy’s interpretation of Clausewitz’s work can be found in Understanding War: History and Theory of Combat (New York: Paragon House, 1987), 21-30.

[2] Carl von Clausewitz, On War, translation by Colonel James John Graham (London: N. Trübner, 1873), Book One, Chapter One, Section 17

[3] Dupuy, Understanding War, 26.

Human Factors In Warfare: Dispersion

Photo of Union soldiers on the Antietam battlefield by Alexander Gardener.

As I have written about before, the foundation of Trevor Dupuy’s theories on combat were based on an initial study in 1964 of the relationship between weapon lethality, casualty rates, and dispersion on the battlefield. The historical trend toward greater dispersion was a response to continual increases in the lethality of weapons.

While this relationship might appear primarily technological in nature, Dupuy considered it the result of the human factor of fear on the battlefield. He put it in more human terms in a symposium paper from 1989:

There is one basic reason for the dispersal of troops on modern battlefields: to mitigate the lethal effects of firepower upon troops. As Lewis Richardson wrote in The Statistics of Deadly Quarrels, there is a limit to the amount of punishment human beings can sustain. Dispersion was resorted to as a tactical response to firepower mostly because—as weapons became more lethal in the 17th Century—soldiers were already beginning to disperse without official sanction. This was because they sensed that on the bloody battlefields of that century they were approaching the limit of the punishment men can stand.

Attrition In Future Land Combat

Soldiers with Battery C, 1st Battalion, 82nd Field Artillery Regiment, 1st Brigade Combat Team, 1st Cavalry Division maneuver their Paladins through Hohenfels Training Area, Oct. 26. Photo Credit: Capt. John Farmer, 1st Brigade Combat Team, 1st Cav

Last autumn, U.S. Army Chief of Staff General Mark Milley asserted that “we are on the cusp of a fundamental change in the character of warfare, and specifically ground warfare. It will be highly lethal, very highly lethal, unlike anything our Army has experienced, at least since World War II.” He made these comments while describing the Army’s evolving Multi-Domain Battle concept for waging future combat against peer or near-peer adversaries.

How lethal will combat on future battlefields be? Forecasting the future is, of course, an undertaking fraught with uncertainties. Milley’s comments undoubtedly reflect the Army’s best guesses about the likely impact of new weapons systems of greater lethality and accuracy, as well as improved capabilities for acquiring targets. Many observers have been closely watching the use of such weapons on the battlefield in the Ukraine. The spectacular success of the Zelenopillya rocket strike in 2014 was a convincing display of the lethality of long-range precision strike capabilities.

It is possible that ground combat attrition in the future between peer or near-peer combatants may be comparable to the U.S. experience in World War II (although there were considerable differences between the experiences of the various belligerents). Combat losses could be heavier. It certainly seems likely that they would be higher than those experienced by U.S. forces in recent counterinsurgency operations.

Unfortunately, the U.S. Defense Department has demonstrated a tenuous understanding of the phenomenon of combat attrition. Despite wildly inaccurate estimates for combat losses in the 1991 Gulf War, only modest effort has been made since then to improve understanding of the relationship between combat and casualties. The U.S. Army currently does not have either an approved tool or a formal methodology for casualty estimation.

Historical Trends in Combat Attrition

Trevor Dupuy did a great deal of historical research on attrition in combat. He found several trends that had strong enough empirical backing that he deemed them to be verities. He detailed his conclusions in Understanding War: History and Theory of Combat (1987) and Attrition: Forecasting Battle Casualties and Equipment Losses in Modern War (1995).

Dupuy documented a clear relationship over time between increasing weapon lethality, greater battlefield dispersion, and declining casualty rates in conventional combat. Even as weapons became more lethal, greater dispersal in frontage and depth among ground forces led daily personnel loss rates in battle to decrease.

The average daily battle casualty rate in combat has been declining since 1600 as a consequence. Since battlefield weapons continue to increase in lethality and troops continue to disperse in response, it seems logical to presume the trend in loss rates continues to decline, although this may not necessarily be the case. There were two instances in the 19th century where daily battle casualty rates increased—during the Napoleonic Wars and the American Civil War—before declining again. Dupuy noted that combat casualty rates in the 1973 Arab-Israeli War remained roughly the same as those in World War II (1939-45), almost thirty years earlier. Further research is needed to determine if average daily personnel loss rates have indeed continued to decrease into the 21st century.

Dupuy also discovered that, as with battle outcomes, casualty rates are influenced by the circumstantial variables of combat. Posture, weather, terrain, season, time of day, surprise, fatigue, level of fortification, and “all out” efforts affect loss rates. (The combat loss rates of armored vehicles, artillery, and other other weapons systems are directly related to personnel loss rates, and are affected by many of the same factors.) Consequently, yet counterintuitively, he could find no direct relationship between numerical force ratios and combat casualty rates. Combat power ratios which take into account the circumstances of combat do affect casualty rates; forces with greater combat power inflict higher rates of casualties than less powerful forces do.

Winning forces suffer lower rates of combat losses than losing forces do, whether attacking or defending. (It should be noted that there is a difference between combat loss rates and numbers of losses. Depending on the circumstances, Dupuy found that the numerical losses of the winning and losing forces may often be similar, even if the winner’s casualty rate is lower.)

Dupuy’s research confirmed the fact that the combat loss rates of smaller forces is higher than that of larger forces. This is in part due to the fact that smaller forces have a larger proportion of their troops exposed to enemy weapons; combat casualties tend to concentrated in the forward-deployed combat and combat support elements. Dupuy also surmised that Prussian military theorist Carl von Clausewitz’s concept of friction plays a role in this. The complexity of interactions between increasing numbers of troops and weapons simply diminishes the lethal effects of weapons systems on real world battlefields.

Somewhat unsurprisingly, higher quality forces (that better manage the ambient effects of friction in combat) inflict casualties at higher rates than those with less effectiveness. This can be seen clearly in the disparities in casualties between German and Soviet forces during World War II, Israeli and Arab combatants in 1973, and U.S. and coalition forces and the Iraqis in 1991 and 2003.

Combat Loss Rates on Future Battlefields

What do Dupuy’s combat attrition verities imply about casualties in future battles? As a baseline, he found that the average daily combat casualty rate in Western Europe during World War II for divisional-level engagements was 1-2% for winning forces and 2-3% for losing ones. For a divisional slice of 15,000 personnel, this meant daily combat losses of 150-450 troops, concentrated in the maneuver battalions (The ratio of wounded to killed in modern combat has been found to be consistently about 4:1. 20% are killed in action; the other 80% include mortally wounded/wounded in action, missing, and captured).

It seems reasonable to conclude that future battlefields will be less densely occupied. Brigades, battalions, and companies will be fighting in spaces formerly filled with armies, corps, and divisions. Fewer troops mean fewer overall casualties, but the daily casualty rates of individual smaller units may well exceed those of WWII divisions. Smaller forces experience significant variation in daily casualties, but Dupuy established average daily rates for them as shown below.

For example, based on Dupuy’s methodology, the average daily loss rate unmodified by combat variables for brigade combat teams would be 1.8% per day, battalions would be 8% per day, and companies 21% per day. For a brigade of 4,500, that would result in 81 battle casualties per day, a battalion of 800 would suffer 64 casualties, and a company of 120 would lose 27 troops. These rates would then be modified by the circumstances of each particular engagement.

Several factors could push daily casualty rates down. Milley envisions that U.S. units engaged in an anti-access/area denial environment will be constantly moving. A low density, highly mobile battlefield with fluid lines would be expected to reduce casualty rates for all sides. High mobility might also limit opportunities for infantry assaults and close quarters combat. The high operational tempo will be exhausting, according to Milley. This could also lower loss rates, as the casualty inflicting capabilities of combat units decline with each successive day in battle.

It is not immediately clear how cyberwarfare and information operations might influence casualty rates. One combat variable they might directly impact would be surprise. Dupuy identified surprise as one of the most potent combat power multipliers. A surprised force suffers a higher casualty rate and surprisers enjoy lower loss rates. Russian combat doctrine emphasizes using cyber and information operations to achieve it and forces with degraded situational awareness are highly susceptible to it. As Zelenopillya demonstrated, surprise attacks with modern weapons can be devastating.

Some factors could push combat loss rates up. Long-range precision weapons could expose greater numbers of troops to enemy fires, which would drive casualties up among combat support and combat service support elements. Casualty rates historically drop during night time hours, although modern night-vision technology and persistent drone reconnaissance might will likely enable continuous night and day battle, which could result in higher losses.

Drawing solid conclusions is difficult but the question of future battlefield attrition is far too important not to be studied with greater urgency. Current policy debates over whether or not the draft should be reinstated and the proper size and distribution of manpower in active and reserve components of the Army hinge on getting this right. The trend away from mass on the battlefield means that there may not be a large margin of error should future combat forces suffer higher combat casualties than expected.

Logistics in Trevor Dupuy’s Combat Models

Trevor N. Dupuy, Numbers, Predictions and War: Using History to Evaluate Combat Factors and Predict the Outcome of Battles (Indianapolis; New York: The Bobbs-Merrill Co., 1979), p. 79

Mystics & Statistics reader Stiltzkin posed two interesting questions in response to my recent post on the new blog, Logistics in War:

Is there actually a reliable way of calculating logistical demand in correlation to “standing” ration strength/combat/daily strength army size?

Did Dupuy ever focus on logistics in any of his work?

The answer to his first question is, yes, there is. In fact, this has been a standard military staff function since before there were military staffs (Martin van Creveld’s book, Supplying War: Logistics from Wallenstein to Patton (2nd ed.) is an excellent general introduction). Staff officer’s guides and field manuals from various armies from the 19th century to the present are full of useful information on field supply allotments and consumption estimates intended to guide battlefield sustainment. The records of modern armies also contain reams of bureaucratic records documenting logistical functions as they actually occurred. Logistics and supply is a woefully under-studied aspect of warfare, but not because there are no sources upon which to draw.

As to his second question, the answer is also yes. Dupuy addressed logistics in his work in a couple of ways. He included two logistics multipliers in his combat models, one in the calculation for the battlefield effects of weapons, the Operational Lethality Index (OLI), and also as one element of the value for combat effectiveness, which is a multiplier in his combat power formula.

Dupuy considered the impact of logistics on combat to be intangible, however. From his historical study of combat, Dupuy understood that logistics impacted both weapons and combat effectiveness, but in the absence of empirical data, he relied on subject matter expertise to assign it a specific value in his model.

Logistics or supply capability is basic in its importance to combat effectiveness. Yet, as in the case of the leadership, training, and morale factors, it is almost impossible to arrive at an objective numerical assessment of the absolute effectiveness of a military supply system. Consequently, this factor also can be applied only when solid historical data provides a basis for objective evaluation of the relative effectiveness of the opposing supply capabilities.[1]

His approach to this stands in contrast to other philosophies of combat model design, which hold that if a factor cannot be empirically measured, it should not be included in a model. (It is up to the reader to decide if this is a valid approach to modeling real-world phenomena or not.)

Yet, as with many aspects of the historical study of combat, Dupuy and his colleagues at the Historical Evaluation Research Organization (HERO) had taken an initial cut at empirical research on the subject. In the late 1960s and early 1970s, Dupuy and HERO conducted a series of studies for the U.S. Air Force on the historical use of air power in support of ground warfare. One line of inquiry looked at the effects of air interdiction on supply, specifically at Operation STRANGLE, an effort by the U.S. and British air forces to completely block the lines of communication and supply of German ground forces defending Rome in 1944.

Dupuy and HERO dug deeply into Allied and German primary source documentation to extract extensive data on combat strengths and losses, logistical capabilities and capacities, supply requirements, and aircraft sorties and bombing totals. Dupuy proceeded from a historically-based assumption that combat units, using expedients, experience, and training, could operate unimpaired while only receiving up to 65% of their normal supply requirements. If the level of supply dipped below 65%, the deficiency would begin impinging on combat power at a rate proportional to the percentage of loss (i.e., a 60% supply rate would impose a 5% decline, represented as a combat effectiveness multiplier of .95, and so on).

Using this as a baseline, Dupuy and HERO calculated the amount of aerial combat power the Allies needed to apply to impact German combat effectiveness. They determined that Operation STRANGLE was able to reduce German supply capacity to about 41.8% of normal, which yielded a reduction in the combat power of German ground combat forces by an average of 6.8%.

He cautioned that these calculations were “directly relatable only to the German situation as it existed in Italy in late March and early April 1944.” As detailed as the analysis was, Dupuy stated that it “may be an oversimplification of a most complex combination of elements, including road and railway nets, supply levels, distribution of targets, and tonnage on targets. This requires much further exhaustive analysis in order to achieve confidence in this relatively simple relationship of interdiction effort to supply capability.”[2]

The historical work done by Dupuy and HERO on logistics and combat appears unique, but it seems highly relevant. There is no lack of detailed data from which to conduct further inquiries. The only impediment appears to be lack of interest.

NOTES

 [1] Trevor N. Dupuy, Numbers, Predictions and War: Using History to Evaluate Combat Factors and Predict the Outcome of Battles (Indianapolis; New York: The Bobbs-Merrill Co., 1979), p. 38.

[2] Ibid., pp. 78-94.

[NOTE: This post was edited to clarify the effect of supply reduction through aerial interdiction in the Operation STRANGLE study.]

Logistics In War

“Amateurs study tactics, armchair generals study strategy, but professionals study logistics,” as the old saw goes. While the veracity of this statement is debatable, there can be little doubt that the study and appreciation of the role of sustainment in warfare lags behind that of the sexier topics of strategy and tactics.  A new blog, Logistics in War, [also on Facebook (https://www.facebook.com/logisticsinwar/) and Twitter (@logisticsinwar)] is seeking to change that.

The anonymous and somewhat mysterious purveyor of the blog bills it as “a public, unofficial, ‘Professional Military Education’ site,” the purpose of which is “to instigate and inspire, continue and create, a discussion on military logistics that is so often sorely lacking (or if it does occur, does so behind closed doors).”

It seems safe to conclude that the blog’s owner is an Australian Army loggie, however: “Although the blog currently reflects an Australian and Army orientation, its vision is to become broadly applicable; to reflect the many different approaches to logistics as practiced by different military Services, the Joint domain, and militaries of all persuasions.”

The initial posts range in subject from a list of suggested readings about logistics, to the impact of sustainment in battle in recent history, to the challenges of supplying combat forces in the multi-domain battle construct. The writing is crisp, clear, and professional, and the questions and topics addressed are of undeniable importance. Logistics in War is a welcome addition to the online conversation about warfare, and is well worth the time to peruse. It will be very interesting to watch it progress and grow.

Trevor Dupuy and Historical Trends Related to Weapon Lethality

There appears to be renewed interest in U.S. Army circles in Trevor Dupuy’s theory of a historical relationship between increasing weapon lethality, declining casualty rates, and greater dispersion on the battlefield. A recent article by Army officer and strategist Aaron Bazin, “Seven Charts That Help Explain American War” at The Strategy Bridge, used a composite version of two of Dupuy’s charts to explain the American military’s attraction to technology. (The graphic in Bazin’s article originated in a 2009 Australian Army doctrinal white paper, “Army’s Future Land Operating Concept,” which evidently did not cite Dupuy as the original source for the charts or the associated concepts.)

John McRea, like Bazin a U.S. Army officer, and a founding member of The Military Writer’s Guild, reposted Dupuy’s graphic in a blog post entitled “Outrageous Fortune: Spears and Arrows,” examining tactical and economic considerations in the use of asymmetrical technologies in warfare.

Dr. Conrad Crane, Chief of Historical Services for the U.S. Army Heritage and Education Center at the Army War College, also referenced Dupuy’s concepts in his look at human performance requirements, “The Future Soldier: Alone in a Crowd,” at War on the Rocks.

Dupuy originally developed his theory based on research and analysis undertaken by the Historical Evaluation and Research Organization (HERO) in 1964, for a study he directed, “Historical Trends Related to Weapon Lethality.” (Annex I, Annex II, Annex III). HERO had been contracted by the Advanced Tactics Project (AVTAC) of the U.S. Army Combat Developments Command, to provide unclassified support for Project OREGON TRAIL, a series of 45 classified studies of tactical nuclear weapons, tactics, and organization, which took 18 months to complete.

AVTAC asked HERO “to identify and analyze critical relationships and the cause-effect aspects of major advances in the lethality of weapons and associated changes in tactics and organization” from the Roman Era to the present. HERO’s study itself was a group project, incorporating 58 case studies from 21 authors, including such scholars as Gunther E. Rothenberg, Samuel P. Huntington, S.L.A. Marshall, R. Ernest Dupuy, Grace P. Hayes, Louis Morton, Peter Paret, Stefan T. Possony, and Theodore Ropp.

Dupuy synthesized and analyzed these case studies for the HERO study’s final report. He described what he was seeking to establish in his 1979 book, Numbers, Predictions and War: Using History to Evaluate Combat Factors and Predict the Outcome of Battles.

If the numbers of military history mean anything, it appears self-evident that there must be some kind of relationship between the quantities of weapons employed by opposing forces in combat, and the number of casualties suffered by each side. It also seems fairly obvious that some weapons are likely to cause more casualties than others, and that the effectiveness of weapons will depend upon their ability to reach their targets. So it becomes clear that the relationship of weapons to casualties is not quite the simple matter of comparing numbers to numbers. To compare weapons to casualties it is necessary to know not only the numbers of weapons, but also how many there are of each different type, and how effective or lethal each of these is.

The historical relationship between lethality, casualties, and dispersion that Dupuy deduced in this study provided the basis for his subsequent quest to establish an empirically-based, overarching theory of combat, which he articulated through his Quantified Judgement Model. Dupuy refined and updated the analysis from the 1964 HERO study in his 1980 book, The Evolution of Weapons and Warfare.

Mosul and ISF Combat Effectiveness

The situation in Mosul, 16-19 December 2016 (Institute for the Study of War)

After a period of “operational refit,” Iraqi Security Forces (ISF) waging battle with Daesh fighters for control of the city of Mosul launched a new phase of their advance on 29 December. The initial phase of the assault, which began on 17 October 2016, ground to a halt due to strong Daesh resistance and heavy casualties among the Iraqi Counterterrorism Service (CTS) troops spearheading the operation.

For the new offensive, the CTS was reinforced with additional Iraqi Army ground units, as well as an armored element of the Federal Police. Additional U.S. combat forces and advisors have also been moved closer to the front lines in support.

Although possessing an enormous manpower advantage over the Daesh defenders, ISF had managed to secure only one-quarter of the city in two months of combat. This is likely due to the fact that the only ISF elements that have demonstrated any offensive combat effectiveness have been the CTS and the Popular Mobilization Forces (PMF, or Hash’d al Shaabi) Iraqi Shi’a militia mobilized by Grand Ayatollah Ali Sistani in 2014. PMF brigades hold the western outskirts of the city, but thus far have been restrained from entering it for fear of provoking sectarian violence with the mostly Sunni residents.

Daesh defenders, believed to number only from 3,000-5,000 at the outset of the battle, have had the luxury of fighting against only one axis of advance and within urban terrain filled with trapped civilians, which they have used as human shields. They mounted a particularly effective counterattack against the CTS using vehicle-borne improvised explosive devices (VBIEDs), which halted the initial offensive in mid-December. ISF casualties appear to be concentrated in the elite 1st Special Operations Brigade (the so-called “Golden Division”) of the CTS. An unnamed Pentagon source was quoted as stating that the Golden Division’s maneuver battalions had incurred “upwards of 50 percent casualties,” which, if sustained, would have rendered it combative ineffective in less than a month.

The Iraqi government has come to rely on the Golden Division to generate reliable offensive combat power. It spearheaded the attacks that recovered Tikrit, Ramadi, and Fallujah earlier in the year. Originally formed in 2004 as the non-sectarian Iraqi Special Operations Forces brigade, the Golden Division was amalgamated into the CTS in 2007 along with specialized counterterrorism and national police elements. Although intended for irregular warfare, the CTS appears to be the only Iraqi military force capable of effective conventional offensive combat operations, likely due to higher level of combat effectiveness relative to the rest of the ISF, as well as its interoperability with U.S. and Coalition supporting forces.

Historically, the Iraqi Army has not demonstrated a high level of overall combat effectiveness. Trevor Dupuy’s analysis of the performance of the various combatants in the 1973 Arab-Israeli War ranked the Iraqi Army behind that of the Israelis, Jordanians, Egyptians, and Syrians. He estimated the Israelis to have a 3.43 to 1.00 combat effectiveness advantage over the Iraqis in 1973. Dupuy credited the Iraqis with improved effectiveness following the 1980-88 Iran-Iraq War in his pre-war estimate of the outcome of the 1990-91 Gulf War. This turned out to be erroneous; overestimation of Iraqi combat effectiveness in part led Dupuy to predict a higher casualty rate for U.S. forces than actually occurred. The ineffective performance of the Iraqi Army in 2003 should have not surprised anyone.

The relative success of the CTS can be seen as either indicative of the general failure of the decade-long U.S. effort to rebuild an effective Iraqi military establishment, or as an exemplary success of the U.S. Special Operations Forces model for training and operating with indigenous military forces. Or both.