Lessons Learned from World War 2 Strategic Bombardment

Let us not be zealots. Let us not plunge thoughtlessly from the old and known to the new and untried. Let us not claim that the airplane has outmoded all other machines of war. Rather, let us be content with an evident truth: The air force has introduced a new and different means of waging war. (p. 85)

Haywood Hansell

As Hansell highlighted, air power revolutionised war by allowing the focusing of force on the enemy’s vulnerable areas without having to meet its forces ‘in the field’. There are now a few essential books on strategic bombardment that provide historical depth to its development primarily during the Second World War. Works such as Bombers and the Bombed – Allied Air War Over Europe by Richard Overy, Among the Dead Cities by A.C. Grayling, and Air Power and Warfare – A Century of Theory and History by Tami Davis Biddle provide a rich contextual background within which Phil Haun’s compilation sits.

Phil Haun has compiled the lectures of the Air Corps Tactical School (ACTS) as a means of capturing some of the primary sources that led to the development of the American approach to strategic bombardment. The theories focused specifically on high altitude daylight precision bombing (HADPB).

The lectures in Haun’s work were developed during the formative period of air power, following on from the landmark work, Command of the Air, by Giulio Douhet, which advocated for the use of air power for strategic bombardment of civilian populations and cities on the assumption that it would destroy morale and force populations to capitulate. Douhet’s work focused on the importance of gaining command of the air and the direction of air power to particular targets.

What makes Haun’s compilation compelling, and its most significant contribution to the study of air power is that it preserves nascent thinking about how to put novel theories into practice. The work also highlights the perennial struggle between the development of strategic air power – to ostensibly use air power as a means to victory on its own – or the development of air power capabilities that primarily support naval and land forces.

Although the technology has developed beyond what the authors of these lectures could have imagined, their ideas and arguments have a direct link and relevance to conceptions of strategic strike, and bombardment in depth. For example, Major – later General – Muir Fairchild’s discussion of the ‘National Economic Structure’ (pp. 140-64) in his 5 April 1939 lecture to the ACTS finds resonance in the targeting of Daesh oil and cash stores during Operation INHERENT RESOLVE as a means to removing the economic support to its military operations in Iraq and Syria.

This compilation of lectures is recommended for military professionals, and students of military history and air power, who want access to primary sources that demonstrate the fundamental ideas on strategic bombardment and how air power could be used independently as a means of forcing the rapid capitulation of the enemy.

The book is comprised of several lectures delivered at ACTS at Maxwell Field, Alabama, between 1936 and 1940, and demonstrates the development of American logic and assumptions regarding the best use of a new capability – aerial bombardment – to achieve strategic outcomes.

In his ‘Notes on the Text’ (pp. xv-xvi), Haun explained the criteria he used to select the ten lectures published in the book. First, the lectures were the most quoted in subsequent publications on U.S. strategic bombardment and were therefore considered by Haun to be the most important.

Second, the lectures demonstrated the most mature thinking on the theory of American strategic bombing before the entry of the United States into the Second World War in December 1941. Third, these lectures were delivered to the largest number of students at ACTS between 1938 and 1941. Fourth, the students mentioned above became the officers who planned and conducted bombardment in Germany and Japan. Fifth, there were the best-preserved lectures. Finally, and pragmatically, not all ACTS lectures could be physically included in a single volume work.

The lectures were delivered by officers who were experienced aviators, and some had tertiary qualifications, though only a few had combat experience. Only a few, such as Major – later Lieutenant-General – Harold George and Fairchild, had completed some professional military education.

This does not distract from the utility of the lectures presented here, as they demonstrate a practitioner’s approach to wrestling with the dilemma of how to maximise the utility of a new weapon of war, and to avoid the protracted stalemate on the Western Front only 20 years before the time these lectures were written.

Haun’s introductory sections to the book provide an overview of the development of air power theory during the inter-war period. Aside from Douhet, the most important ideas that influenced the development of air power theory in the United Kingdom and the United States can be traced to a few individuals. Major-General Hugh Trenchard became the first Chief of the Air Staff of the newly established Royal Air Force in 1918. He influenced the development of British strategic bombardment theory, principally reference to attacking the enemy’s morale, which was not as blunt as Douhet’s advocacy for the bombing of the civilian population.

Brigadier General William ‘Billy’ Mitchell proposed the creation of an independent air service alongside his ideas on strategic bombardment that focused on the selection of targets that would most quickly degrade the enemy’s capacity to fight and therefore shorten the war. The inter-war theorists minimised discussion about the effect of bombardment on the civilian population, with the practice of bombardment of cities by both sides in the Second World War.

This culminated in dropping of the atomic bomb on Nagasaki and Hiroshima in 1945. The effectiveness of strategic bombardment of cities remains a subject of enduring controversy,¹

The first two chapters provide an elucidation of the understanding of strategy, air power, and warfare as held by the lecturers. The enduring nature of war is discussed or mentioned in these chapters, such as Captain – later Major General – Haywood Hansell’s statement that:

War is a furtherance of national policy by violence. Since nations find the real fulfilment of their policies in peace, the real object of war is not the continuance of violence, but the establishment of a satisfactory peace.’ (p. 75)

The authors of these lectures also grappled with the industrialised nature of warfare that was so grimly demonstrated on the Western Front from 1914 to 1918. George, in ‘An Inquiry into the Subject of “War”,’ noted what he perceived to be the increased vulnerability of industrialised societies, due to their:

[S]usceptibility to defeat by the interruption of this economic web […] connected therewith is the industrial fabric which is absolutely essential for modern war. (p. 43)

This theme is continued and further examined by Fairchild’s lectures in chapters five and six.

Perhaps the least relevant lectures are those in chapter three, which are very technical and limited to the capabilities available at the time the lectures were written. Lieutenant – later Brigadier General – Kenneth Walker’s ‘Driving Home the Bombardment Attack’ discussed the tactics and formations that he considered the most effective for the bomber force to penetrate enemy air defence. They represent rudimentary ideas that were yet to be tested.

Haun commented that Walker’s ideas proved to be right in that bomber formations successfully penetrated air defences, yet only focused on single raids rather than the cumulative effect of aerial attacks over time (p. 98). Major Frederick Hopkins’ lecture, ‘Tactical Offense and Tactical Defense’ considered the attrition rate of the bomber force and consequent ability to conduct offensive bomber operations. These lectures discuss the tactical viability of the bomber force and its impact on successful offensive bombing operations. However, they did not account for the development of radar, which had a dramatic impact on the effectiveness of bombardment, and was being developed at the time of their writing.

Captain – later General – Laurence Kuter’s lecture on the ‘Practical Bombing Probabilities’ considered several factors that determined the accuracy of delivery and effectiveness of bombardment. Kuter’s lecture was delivered in 1939 while the Norden bombsight continued in its development. Although the bombsight would not be used until the war, the concepts and ideas discussed by Kuter represented necessary rudimentary steps in thinking about bombardment accuracy.

From the ‘Practical Bombing Probabilities Problem,’ we can draw a direct link to the development of elaborate weapons effects information, and other considerations that affect bombing accuracy. The factors that determine ‘how many bombs it takes to hit and sink a battleship’ or any other target are now answered by software such as the Joint Air-to-Surface Weaponeering System, and databases such as the Joint Munitions Effectiveness Manual. These targeting tools are essential for the planning of strike missions and are directed towards maximising accuracy while ensuring a high ‘probability of kill’ (Pk).

Chapters five, six and seven covers the theories of Fairchild are perhaps the most useful lectures as they are still relevant today. Fairchild’s work provided insight into the dilemma of how to effectively use air power for strategic effect versus using air forces to support land and naval forces.

As Haun highlighted, with the development of the Norden bombsight and the B-17 Flying Fortress, the next issue was to determine what targets could be struck to most effectively and rapidly result in victory (p. 139). Fairchild’s work is based on studies by Donald Wilson, who provided an analysis of America’s infrastructure and its vulnerability to attack because U.S. isolationism at the time prevented the collection of intelligence about the Germans and Japanese.

One of the more interesting aspects of Fairchild’s lecture ‘National Economic Structure’ (pp. 140-64) is his discussion of the effectiveness of attacking an enemy population’s morale versus the enemy’s war-making capacity. He concluded that because of the adaptability of ‘man’ the fear initially caused by strategic bombardment to becomes ineffective over time.

This was certainly borne out by the evident ‘Blitz Spirit’ and resolve within British society as the result of bombardment by the Luftwaffe in 1941. Fairchild went on to state that a more humane – and certainly consistent with the laws of war – approach was to understand the target as a system. He said:

Complete information concerning the targets that comprise this objective is available and should be gathered during peace. Only by careful analysis – by painstaking investigation, will it be possible to select the line of action that will most efficiently and effectively accomplish our purpose, and provide the correct employment of the air force during war. It is a study for the economist – the statistician – the technical expert – rather than for the soldier. (p. 146)

This is precisely the function of ‘target systems analysis’ today, which is essential for understanding the vulnerabilities of a system in order to identify the components that can be affected to destroy or degrade the operation of the system. The United States Strategic Bombing Survey (USSBS) acknowledged that the factors of production identified by Fairchild – transportation, petroleum refineries, and electrical power stations – were indeed critical vulnerabilities in the German economy (p. 178).

The maturity of such a system was perhaps most evident in the command and control established to plan and execute the air war against Iraq in the 1991 Gulf War. Using the small planning cell established during the Cold War called ‘Checkmate’, Colonel John Warden III developed a plan to use air power to defeat Iraq by targeting it’s ‘centres of gravity.’²

This included obtaining control of the air by destroying Iraq’s air defences to maximise freedom of manoeuvre by the U.S. and allied air forces to strike at command and control nodes, transportation, power and communications.³

Haun’s compilation of lectures certainly has contemporary utility by providing a good background to some of the ideas and theories that form the foundation of the practice of contemporary strategic strike. However, the book is limited by its focus on a very particular part of the development of U.S. strategic bombardment theory.

Consequently, Haun’s work is a point in time reference that must be read alongside other works mentioned previously, and also with the reports of the United States Strategic Bombing Survey to provide a rich context and anchor for this work.

As Eliot Cohen once argued:

Air power is an unusually seductive form of military strength, in part because, like modern courtship, it appears to offer gratification without commitment.⁴

Air power has provided nations with the ability to coerce and deter others from acting in particular ways. Haun’s work ends with a summary of the perpetual struggle between the apportionment of air power resources towards strategic strike or to support other forces. The development of exquisite multi-role capabilities has alleviated the need to choose between these broad air power roles. Air power has also allowed nations to take swift and decisive action against others in a manner that does not commit it to long term ‘boots on the ground’, as Cohen’s words highlighted.

The 1991 Gulf War demonstrated the effectiveness of strategic bombardment when planned and synchronised with the wider joint and combined campaign.

So successful was the use of air power in the 1991 Gulf War, that it prompted the authors of Military Lessons of the Gulf War to proclaim:

[T]he inescapable conclusion […] that air power virtually brought Iraq to its knees, and the air war showed that air power may be enough to win some conflicts.⁵

The use of air power, however, must be much more discerning. In the information age, the simple targeting of physical infrastructure and systems are no longer solely effective. The prolonged and ongoing wars in Afghanistan and Iraq have perhaps demonstrated the limitations of the kinetic solutions offered by strategic bombardment. Ideologies that fuelled these conflicts cannot be simply ‘bombed’ into submission.

The main effort is no longer necessarily fought with the bomber or fighter force, but rather in the memes and interactions on social media.⁶

Perhaps the next evolution is to incorporate some ‘axiological targeting’ considerations – which requires understanding the human population as a system, including understanding what is of value to them.⁷

Relative to the conduct of war by land or sea, the use of the air for warfare is a little over one hundred years old. The utility of strategic strike continues to evolve and will present more opportunities and challenges.

Many of the ideas developed and taught at ACTS lie at the foundation of the theories and practices in place today and form a humble yet essential contribution to the evolution of air power theory.

Group Captain Jo Brick is a Legal Officer in the Royal Australian Air Force. She is currently the Chief of Staff, Australian Defence College. She has served on a number of operational and staff appointments from the tactical to the strategic levels of the Australian Defence Force. Group Captain Brick is a graduate of the Australian Command and Staff Course. She holds a Master of International Security Studies (Deakin University), a Master of Laws (Australian National University) and a Master (Advanced) of Military and Defence Studies (Honours) (Australian National University).

She is a Member of the Military Writers Guild, an Associate Editor for The Strategy Bridge, and an Editor for The Central Blue.

She can be found on Twitter at @clausewitzrocks.

This article was published by Central Blue on April 5, 2020.

 

 

 

1. See Charles S. Maier, ‘Targeting the City: Debates and silences about aerial bombing of World War II’, International Review of the Red Cross, 87:859 (2005)..
2. Tom Clancy, with General Chuck Horner (ret’d), Every Man a Tiger – The Gulf War Air Campaign (New York: Berkley Book, 2000), pp. 256-7. See also Thomas A. Kearney and Eliot A. Cohen. Gulf War Air Power Survey – Summary Report, 1993
3.  Clancy and Horner, Every Man, 372-3..
4. Eliot Cohen, ‘The Mystique of US Air Power’, Foreign Affairs, (1994)..
5. Rod Alonso, ‘The Air War’ in Bruce W Watson, Bruce George MP, Peter Tsouras, and BL Cyr. Military Lessons of the Gulf War (London: Greenhill Books, 1991), p. 77..
6. See P.W. Singer and Emerson T. Brooking, Like War – The Weaponization of Social Media(New York: Houghton Mifflin Harcourt Publishing Company, 2018).
7. See Peter Wijninga and Richard Szafranski, ‘Beyond Utility Targeting: Toward Axiological Air Operations’, Aerospace Power Journal (Winter 2000).