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.

U.S. Army Doctrine and Future Warfare

Pre-war U.S. Army warfighting doctrine led to fielding the M10, M18 and M36 tank destroyers to counter enemy tanks. Their relatively ineffective performance against German panzers in Europe during World War II has been seen as the result of flawed thinking about tank warfare. [Wikimedia]

Two recently published articles on current U.S. Army doctrine development and the future of warfare deserve to be widely read:

“An Army Caught in the Middle Between Luddites, Luminaries, and the Occasional Looney,”

The first, by RAND’s David Johnson, is titled “An Army Caught in the Middle Between Luddites, Luminaries, and the Occasional Looney,” published by War on the Rocks.

Johnson begins with an interesting argument:

Contrary to what it says, the Army has always been a concepts-based, rather than a doctrine-based, institution. Concepts about future war generate the requirements for capabilities to realize them… Unfortunately, the Army’s doctrinal solutions evolve in war only after the failure of its concepts in its first battles, which the Army has historically lost since the Revolutionary War.

The reason the Army fails in its first battles is because its concepts are initially — until tested in combat — a statement of how the Army “wants to fight” and rarely an analytical assessment of how it “will have to fight.”

Starting with the Army’s failure to develop its own version of “blitzkrieg” after World War I, Johnson identified conservative organizational politics, misreading technological advances, and a stubborn refusal to account for the capabilities of potential adversaries as common causes for the inferior battlefield weapons and warfighting methods that contributed to its impressive string of lost “first battles.”

Conversely, Johnson credited the Army’s novel 1980s AirLand Battle doctrine as the product of an honest assessment of potential enemy capabilities and the development of effective weapon systems that were “based on known, proven technologies that minimized the risk of major program failures.”

“The principal lesson in all of this” he concluded, “is that the U.S. military should have a clear problem that it is trying to solve to enable it to innovate, and is should realize that innovation is generally not invention.” There are “also important lessons from the U.S. Army’s renaissance in the 1970s, which also resulted in close cooperation between the Army and the Air Force to solve the shared problem of the defense of Western Europe against Soviet aggression that neither could solve independently.”

“The US Army is Wrong on Future War”

The other article, provocatively titled “The US Army is Wrong on Future War,” was published by West Point’s Modern War Institute. It was co-authored by Nathan Jennings, Amos Fox, and Adam Taliaferro, all graduates of the School of Advanced Military Studies, veterans of Iraq and Afghanistan, and currently serving U.S. Army officers.

They argue that

the US Army is mistakenly structuring for offensive clashes of mass and scale reminiscent of 1944 while competitors like Russia and China have adapted to twenty-first-century reality. This new paradigm—which favors fait accompli acquisitions, projection from sovereign sanctuary, and indirect proxy wars—combines incremental military actions with weaponized political, informational, and economic agendas under the protection of nuclear-fires complexes to advance territorial influence. The Army’s failure to conceptualize these features of the future battlefield is a dangerous mistake…

Instead, they assert that the current strategic and operational realities dictate a far different approach:

Failure to recognize the ascendancy of nuclear-based defense—with the consequent potential for only limited maneuver, as in the seventeenth century—incurs risk for expeditionary forces. Even as it idealizes Patton’s Third Army with ambiguous “multi-domain” cyber and space enhancements, the US Army’s fixation with massive counter-offensives to defeat unrealistic Russian and Chinese conquests of Europe and Asia misaligns priorities. Instead of preparing for past wars, the Army should embrace forward positional and proxy engagement within integrated political, economic, and informational strategies to seize and exploit initiative.

The factors they cite that necessitate the adoption of positional warfare include nuclear primacy; sanctuary of sovereignty; integrated fires complexes; limited fait accompli; indirect proxy wars; and political/economic warfare.

“Given these realities,” Jennings, Fox, and Taliaferro assert, “the US Army must adapt and evolve to dominate great-power confrontation in the nuclear age. As such, they recommend that the U.S. (1) adopt “an approach more reminiscent of the US Army’s Active Defense doctrine of the 1970s than the vaunted AirLand Battle concept of the 1980s,” (2) “dramatically recalibrate its approach to proxy warfare; and (3) compel “joint, interagency and multinational coordination in order to deliberately align economic, informational, and political agendas in support of military objectives.”

Future U.S. Army Doctrine: How It Wants to Fight or How It Has to Fight?

Readers will find much with which to agree or disagree in each article, but they both provide viewpoints that should supply plenty of food for thought. Taken together they take on a different context. The analysis put forth by Jenninigs, Fox, and Taliaferro can be read as fulfilling Johnson’s injunction to base doctrine on a sober assessment of the strategic and operational challenges presented by existing enemy capabilities, instead of as an aspirational concept for how the Army would prefer to fight a future war. Whether or not Jennings, et al, have accurately forecasted the future can be debated, but their critique should raise questions as to whether the Army is repeating past doctrinal development errors identified by Johnson.