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Book Review - Clearing the Way

US Army Engineers in World War II

Cover of book Clearing the Way by Chris McNab.

by Chris McNab

Casemate Publishers, 2023, 194 pp

Hardcover ISBN: 9781636243863

Digital download: 9781636243870

Reviewed by Nicholas Bosio

It is easy to say that military professionals should study military history, and the underlying theory of our profession, through the lens of context, width, and depth. Yet, how does one study depth? Michael Howard’s seminal article, ‘The Use and Abuse of Military History’, contends that depth is achieved by studying a campaign or war in detail. Through such study, the military professional understands ‘…the omnipresence of chaos, revealing the part played not only by skill and planning and courage, but by sheer good luck.’[i] Such a study gives a grounding in operational and strategic art. Depth also enables the military practitioner to recognise the multidisciplinary nature of the profession of arms. Here, depth is achieved by focusing on an aspect of the profession within a specific conflict or timeframe. Clearing the Way, by Chris McNab, is a perfect example of grappling with this multidisciplinary study of the profession of arms in depth. This depth focuses on an aspect of the profession: military engineering.

At first glance, Clearing the Way appears to be a niche book. However, its pages touch on three factors that any military professional should try to understand. First, we must understand the heritage of our war-fighting skills and techniques. Second, we should know how different parts of the profession (be they musterings, corps, trades, or capabilities) were integrated to support the force as a whole in both ‘the battle’ and ‘the war’. Finally, we should consider what lessons this history can provide for contemporary issues, such as capability development, concept writing, doctrine, and training. Exploring these three factors helps us gain depth within the profession.

Turning to the first topic, the heritage of our war-fighting skills, Clearing the Way delves deep into the US Army’s Corps of Engineers’ technical and tactical thinking. The text provides key extracts from Second World War US engineering doctrine. These wide-ranging extracts cover military engineer force structures, roles, and specific technical guidance for combat and construction engineering. Through McNab’s discussion, we see the full spectrum of engineering principles from which modern concepts such as ‘mobility’, ‘counter-mobility’, ‘survivability’, and ‘sustainment’ are derived. These extracts also delve into engineer planning, or the art of providing advice to manoeuvre planning. By unpacking this heritage, McNab helps today’s military engineers understand the enduring challenges of military engineering. 

What is fascinating for a student of military engineering is the similarities between then and now. From a technical perspective, the military engineering of roads, bridges, and airfields (not to mention much of the combat engineering) has changed little since the Second World War. It is true that, in the civilian arena, engineers have access to more efficient and cost-effective material. However, as Clearing the Way shows, the military engineer must often resort to what is available. How loads affect materials and structures, how to distribute these loads, and the issues of soil bearing have not – conceptually – changed. Nor have the basic building materials available to humankind: timber, rock, poor iron (sometimes called “pig iron”) and steel of unknown quality. Safety Factor Design, so removed from our contemporary civilian-taught Limit-State Design, is seen as paramount in early US military engineering thinking. The emphasis on Safety Factor Design should be no surprise to any military engineer well-versed in dealing with the vagaries of construction in a tactical environment.

McNab’s comparisons with history reminds contemporary military engineers of the importance of ‘expedience’ when conducting engineering design and activities. Many Royal Australian Engineer technical officers are contemptuous of expedient engineering. Such scorn is often derived from a failure to recognise the true meaning of expedience within the engineering context. Expedient does not mean ‘quick and haphazard’, as some assert. Such assertions confuse expedient with expeditious.[ii] Rather, expedient is ‘fit or suitable for the purpose; proper in the circumstances.’[iii] Further, expedient comes from the Latin expediens, meaning to dispatch and put in order.[iv] When considering the meaning and Latin root, we see that all engineering is expedient. Specifically, all engineering tasks seek the most practical outcome given the constraints of the time. Nothing better captures this requirement within a military context than the catch cry of “Keep Them Flying” – an actual statement in the US Army Engineer doctrine of the Second World War.[v] Clearing the Way should remind all of Army’s military engineers that expedient designs – suitable for field and tactical environments, and trained for in peace – should be a military engineer’s norm.

The book also demonstrates how doctrine and, by extension, the US engineer adapted over the war. McNab compares US doctrine with that of other nations, particularly Germany and Japan. Through the book’s analysis of doctrine over time, we see how mobilisation and expansion influenced engineer force structures, technical management, and training development. For example, there is an extract on how training should be framed to expand the force rapidly. Interestingly, this framing heavily emphasises technical training within a tactical environment, including significant tactical training of non-commissioned and commissioned officers.[vi] Through the analysis of doctrine, Clearing the Way illustrates innovation over time, and how the US disseminated information to their combat and force-level units.

By reading Second World War doctrine and the editorial notes within the book, we see the expansive scope of US engineering. What a modern reader should take from this scope is not the tactical aspects of engineering, but ‘…a clear suggestion of the importance of engineer work in supporting the core functionality of a field army, from its sanitation and housing, to its very ability to move across the theatre of operations.’[vii] McNab’s work reinforces the historical place of engineers across the entire spectrum, with weighting towards formation and higher echelons. The criticality of engineers at the force-level is highlighted throughout the book, and the reader is reminded that ‘…the fate of entire campaigns and thousands of personnel could hang on engineering’.[viii]

Within the context of the profession of arms, reading Clearing the Way reminds the military engineer about the importance of flexibility, technical competence, and professional mastery of operational art. Only through such art can a military engineer best adapt technical requirements to the realities of a tactical and campaign setting. Clearing the Way reminds the Royal Australian Engineers that we cannot just be technical engineers. Engineers must also be tacticians, campaign planners, and have full regard for the operational and strategic context – even at the lowest level of engineer command.

Clearing the Way provides much food for thought for the military engineer and the broader military profession. For the military engineer, it should make us pause to consider how we adapt our current civilian technical education to the realities of war.  How do we leverage our education – grounded in efficient design, construction, and complicated quality assurance and control mechanisms – to support the military context? The book does not provide an answer. Nevertheless, it highlights the need for such thinking. For the broader military professional, McNab’s analysis reinforces the importance of echelons and force-level support such as logistics, medical, and engineering. The criticality of the force-level in modern war is starkly seen throughout the Second World War doctrine. Such whole-of-war thinking can become lost in the quest for tactical brilliance. Wars are not won through tactical brilliance alone. Clearing the Way is a book that illuminates Michael Howard’s ‘depth’ by reminding the military professional of the importance of force-level capabilities. Recognising their importance is a vital first step towards success in war over victory in battle


[i]Michael Howard, "The Use and Abuse of Military History," Parameters 11, no. 1 (1981), doi:10.55540/0031-1723.1251.

[ii]Susan Butler, Macquarie Complete Dictionary, iPad App ed. (Sydney, NSW, AUST: Macquarie Dictionary Publishers, 2014).

[iii]Butler, Macquarie Complete Dictionary.

[iv]Butler, Macquarie Complete Dictionary.

[v]Chris McNab, Clearing the Way: US Army Engineers in World War II (Havertown, PA, USA: Casemate Publishers, 2023), 96.

[vi]McNab, Clearing the War, 18-28.

[vii]McNab, Clearing the War, 49.

[viii]McNab, Clearing the War, xiv.

The views expressed in this article and subsequent comments are those of the author(s) and do not necessarily reflect the official policy or position of the Australian Army, the Department of Defence or the Australian Government.

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