Ancient Arts, Modern Ethics, and the New Battlefield

The recent Defence Committee report, Defence in the Grey Zone, brings renewed focus to the challenge of hostile activity below the threshold of conventional war. The term ‘Grey Zone’ suggests a novel ambiguity, a modern strategic dilemma born of new technologies; this ambiguous environment challenges not only our strategic doctrines but also our classical ethical frameworks for conflict. However, while the character of this struggle is undeniably new, its foundational principles are not. The Grey Zone is the modern evolution of ancient principles of statecraft, supercharged by technology and the unique vulnerabilities of a hyperconnected world. To navigate this strategic evolution requires both re-understanding the classical strategists, from Sun Tzu and Kautilya to Clausewitz and Liddell Hart, while simultaneously grappling with profound ethical questions they could never have envisioned.

The Timeless Why

The strategic intent underpinning Grey Zone activity, to “coerce governments or simply erode their ability to function”, is as old as statecraft itself. It is the practical application of “the acme of skill” according to Sun Tzu’s Art of War: “to subdue the enemy without fighting”. This ideal, which finds echoes in the “silent war” of Kautilya’s Arthashastra, offers an intellectual foundation for modern Grey Zone Operations. From a Consequentialist perspective – where morality is based on outcomes alone – this is a grim yet vital calculus aimed at avoiding the greater evil of devastating state-on-state conflict.

The report is replete with modern manifestations of ancient approaches. The use of propaganda and disinformation, “driving a wedge between social groups”, is a direct heir to the classical strategy of attacking an adversary’s societal cohesion. Sun Tzu notes that “all warfare is based on deception”, while Kautilya takes this further, highlighting Bheda (sowing dissent) as one of the four primary tools of statecraft.

The employment of “proxies, including sub-state actors such as rebel groups, mercenaries, criminal gangs, or cyber ‘hacktivists’”, offers the same plausible deniability sought by ancient spymasters. Sun Tzu dedicates an entire chapter to the use of spies for gaining intelligence and manipulating the enemy, while Kautilya describes vast and intricate spy networks as the primary tool for both internal control and external influence.

The report’s observation that “attribution of grey zone activity is often challenging” is equally neither a new nor unforeseen problem but the intended outcome of a strategy designed to achieve political effect while adhering to the Jus Ad Bellum (‘justice to war’, the principles governing righteous initiation of war) principle of Right Intention (from the aggressor’s perspective at least) by avoiding an overt act of war. The goal, now as then, is to weaken the adversary from within, making them politically, economically, and socially unable to resist.

The Transformative What

While the strategic why is timeless, the what – the nature of modern warfare and in particular that of the Grey Zone challenge – has fundamentally transformed. Technology has not merely supplied new tools for the strategist’s arsenal, but created entirely new domains of conflict and systemic vulnerabilities that are without historical precedent.

The report correctly states that “technology has magnified the impact and global reach of grey zone attacks, and identified new areas for prosecuting operations that did not exist a generation ago, particularly regarding cyberattacks”. This has created a geographically boundless cyber domain where adversaries may conduct countless operations on a scale, and at a rate, previously unimaginable – such as the “over 90,000 sub-threshold attacks” launched against the MoD’s networks over just two years.

This digital dependency has birthed a new critical national vulnerability: the physical infrastructure of the internet. The report highlights the “approximately 60 undersea data and energy cables”, whose disruption could have “devastating consequences for the UK”. The fragility of hyperconnectedness is the uniquely modern terrain upon which Grey Zone conflict is waged. Such deliberate targeting of such civilian infrastructure fundamentally challenges the core Jus In Bello (‘justice in war’, rules relating to moral conduct of warfighting itself) principle of discrimination, blurring lines between military and civilian targets and placing civilian life at the centre of the conflict.

The Complex How

Understanding how to operate in this environment requires integrating classical Western military thought with these new realities. Carl von Clausewitz’s central thesis, that “war is merely a continuation of policy with other means”, is perfectly suited to analysing the Grey Zone. For him, this is not something different from war, but in fact a clear example of “real war” – a conflict constrained by its political object, in which actors deliberately avoid escalation to “absolute war”. Thus, hostile acts are not random violence, but the violent “grammar” of a natural political “logic”.

Sir Basil Liddell Hart’s “indirect approach” is equally prescient. Adversaries operate in the Grey Zone precisely to circumvent the UK’s conventional military strength, attacking instead the softer, more vulnerable targets of society. They exploit the “inherent frictions in democracies” and target critical civilian infrastructure to dislocate their opponent psychologically and physically without a direct fight.

Just War in the Shadows

This new reality exposes complex ethical dilemmas. Western liberal democracies find themselves in a Deontological bind – a conflict of duties where moral principles must be upheld regardless of the consequence. They are constrained as their duty to uphold foundational values, such as the balance “between freedom of speech and countering hate speech and disinformation”, creates the very vulnerabilities adversaries exploit. This adherence to Deontological principles clashes with the Consequentialist imperative to protect the state and its people from harm. Autocracies, meanwhile, have no such constraints to employing approaches “which democracies may find unacceptable”. Key democratic principles thus become seams to be exploited. A democratic response however must be effective without sacrificing the very principles it seeks to defend.

This is the central paradox, and what is ultimately at stake. To abandon foundational values – such as the rule of law, governmental accountability, and the protection of civil liberties – in the name of security hands our opponents a decisive grand strategic victory. By abandoning the Virtues we hold sacred, and adopting Deontologically reprehensible approaches, in the desperate pursuit of short-term Consequentialist relief, we become a vile mirror of the oppressive, autocratic, expansionist systems we stand against. This erodes our moral authority and does violence to the cohesive character of our values and our society. The long-term defence of the state is therefore inseparable from the defence of its democratic identity; to sacrifice one is to surrender the other.

The report’s implicit ethical stance therefore, that finely balances key national Virtues, Deontological principles, and ultimately longer-term Consequentialist outcomes, is that UK actions must remain defensive, lawful, and principled, even when its adversary’s are not.

Today’s Grey Zone challenge equally forces a re-evaluation of Just War Theory. Adversaries deliberately violate Jus In Bello principles by targeting the “DIME (Diplomatic, Informational, Military, Economic) model”, making it difficult for a democracy to respond proportionately without stooping to the same level. The perpetual, low-level nature of the conflict also complicates Jus Ad Bellum criteria; what does Last Resort actually mean and look like in a Grey Zone context? The report’s response is to implicitly frame the UK’s posture within this tradition through the justification of Just Cause, specifically self-defence against hostile acts like “sabotage” and “assassination”. The recommended actions are positioned as a proportionate response, short of the Last Resort of conventional war, yet undertaken by a Legitimate (democratic) Authority (HM Government).

Crucially, the report’s fourteen recommendations are a masterclass in Jus Ante Bellum (‘justice before war’, the duty to prevent war and the ethical considerations around preparation for it), seeking above all to build and optimise the conditions for peace and security before a crisis. This focus on “building homeland resilience”, enhancing alliances like the Joint Expeditionary Force (both expanding its membership and increasing its freedom of manoeuvre) and developing cyber defences, is a proactive effort to deter conflict before it can escalate. Even the call for a “whole-of-society approach” is implicitly, yet crucially, an appeal to cultivate national Virtues such as fortitude, prudence, unity, and resilience, to build a citizenry prepared and equipped to withstand the physical and psychological pressures of perpetual sub-threshold conflict and all that implies.

Implicit within this is that in such a state of perpetual conflict, Jus Post Bellum (‘justice after war’, the ethical imperative to rebuild a better peace) may be reinterpreted, not as post-conflict peace-building, but as an ongoing process of societal restoration and resilience in the face of perpetual threats and attacks. Recommendations in the report for the MoD to support civilian authorities and for society to be prepared with stockpiles and skills thus represent prudent Post Bellum planning, ensuring the nation is able to quickly and effectively recover its vital structures and functions and maintain or re-establish normalcy through, and following, otherwise debilitating Grey Zone strikes.

An Ethical and Strategic Synthesis for a New Era

The strategic why of the Grey Zone is timeless: the ambition to subdue an adversary by eroding its power from within. However, as the Defence Committee report details, the what – the nature of the modern battlefield and its targets – has been fundamentally transformed, largely by technology. New domains of conflict include cyberspace, and critical vulnerabilities extend to and through the arteries of our hyperconnected world.

Therefore, the how of effective national response in the Grey Zone must be a sophisticated synthesis of the ancient with the modern, and of strategic innovation with profound ethical clarity. It means applying the enduring strategic principles of statecraft and deterrence, including deception, intelligence, and subversion, while developing entirely new doctrines and capabilities to protect novel vulnerabilities and defend against novel threats.

As we navigate this ambiguous space of perpetual low-intensity conflict, somewhere between peace and war, victory will not be achieved through decisive battle, but through a clear-eyed defence of our democratic principles, an enduring cohesive national resilience to withstand a conflict that is at once everywhere and nowhere, and the wisdom and humility to understand that alongside innovative solutions to unique threats, the oldest techniques of statecraft are more relevant today than ever before.

The challenge for today’s leaders, as the report suggests, is to now translate this complex philosophical, strategic, and practical understanding into tangible doctrine, training, and cross-government action.