Throughout history, ambiguity and clandestine methods in geopolitical manoeuvres have consistently attracted attention. As early as 1948, U.S. diplomat George Kennan highlighted the existence of political warfare in a policy memo, defining it as the application of a nation's resources, excluding direct war, to achieve its national aims. Similar notions, namely “hybrid threats” and the “grey zone” currently dominate dialogues within this context. However, as underscored in our introductory piece, these concepts do suffer from a lack of clear definition, creating a challenge in formulating a uniform framework for comprehension and breeding passivity when it comes to formulating effective responses.

According to our understanding, grey zone coercion is a critical element of the broader concept of "hybrid threats". More precisely, the grey zone can be envisioned as the strategic domain that extends beyond ordinary statecraft but consciously avoids escalating into open conventional warfare. But both concepts can overlap, as their boundaries are rather fuzzy. Therefore, when diplomatic endeavours falter, and conventional warfare seems unlikely to yield the strategic cost-benefit balance aspired to, the grey zone presents itself as an alternative. The appeal lies in the inherent ambiguity for strategic effect and deniability regarding legal contexts that the grey zone can provide. 

Grey zone activities may comprise a diverse range of tactics, all forming an essential part of the “hybrid toolkit”. These tactics can include cyber operations, ranging from infiltrations into critical infrastructure to the theft of sensitive data or orchestration of destructive attacks on a target nation's digital infrastructure. Economic coercion, where states manipulate their economic strengths to destabilize an adversary, is another popular activity. This could take the form of trade wars, financial manipulations, or other forms of economic pressure, which are often strategically employed to maximise plausible deniability. Equally prominent is the use of (dis)information campaigns or political interference. Such campaigns strategically craft narratives to misdirect public sentiment, sow discord or seek to directly influence voting behaviour. They aim to breed confusion, and–most crucially–erode trust in public institutions, including the democratic process. Essentially, the aim is to alienate people from trusting and utilising their own governmental apparatus, thereby turning public sentiment against the institutions meant to serve them. Aided by the proliferation of digital media, these campaigns can propagate rapidly, increasing their potential for disruption. Proxy wars and the use of ambiguous forces, both long-standing tools of geopolitical influence, are also part of grey zone activities. They involve the deployment of third-party actors to engage in conflicts, allowing the sponsoring power to avoid direct confrontation. Lastly, targeted assassinations represent another facet worth mentioning. These are covert operations aiming to remove specific individuals, often key political or military figures, all the while not triggering a full-scale conflict, with the hopes of critically disrupting enemy forces from the top down.

In the grey zone, the boundaries between peace and war are purposefully obscured. Grey zone activities aim to complicate the identification of the real perpetrator, classification of the action, as well as the determination of an appropriate response. However, as the lines of routine statecraft are undoubtedly trespassed when stepping onto grey zone territory, crafting an adequate response is not impossible, should the political will to do so be pivotal. Frequently though, they lead to a paralysis in the decision-making processes of the target nation. The resulting hesitance is a quintessential effect of the grey zone and further buffers the arena of plausible deniability and sub-threshold conflict that capitalises on risk aversion.

The Role of Narrative

The arguably most prolific and primary actors in the grey zone, namely China and Russia, do not conform to the Western terminology of “grey zone”. This distinction perhaps serves as a further testament to the inherent vagueness of these concepts and demonstrates the vital role narrative plays in cultivating the pivotal ambiguity from which the grey zone derives its impactfulness.

Russian tactics that would be defined as "grey zone activities" in the Western context trace back to the Russian Revolution and the necessity to construct a Soviet Sphere of Influence. Throughout the Cold War, the Soviet Union was perceived as a proficient practitioner in the grey zone domain, and Russia, has maintained a similar reputation, especially following the annexation of Crimea in 2014. However, Russia's resort to overt, large-scale conventional force in Ukraine in early 2022, after years of operating in what we call the grey zone, may very well demonstrate the limitations of such activities in achieving tangible strategic success. Moreover, the measures of success in grey zone warfare remain nebulous.

Coincidentally, Russia also rejects the umbrella-terms “hybrid warfare” or “hybrid threat”,  nor does it correspond with Western phase-based classifications of escalation–as opposed to seamless progression. This has not only ramifications for the “sub-conventional” grey zone but also for the “supra-conventional” nuclear dimension. Significantly, despite exploiting the opportunities offered by the grey zone, Russia has coincidently abandoned its long-held, albeit widely distrusted, no-first-use nuclear doctrine. Instead, it has adopted an approach of "escalate to de-escalate", which includes the potential for nuclear "de-escalation" strikes even during the early stages of conflict. 

China, too, does not use the term “grey zone” but refers to “Military Operations Other Than War” (MOOTW). While the grey zone is seen in the West as an ambiguous, coercive tactic that lies beyond the bounds of ordinary statecraft and diplomacy, China regards MOOTW as a seamless extension of statecraft and a legitimate facet of exerting state power, not unlike Russia's mindset. China has frequently utilised MOOTW that fall below the level of armed conflict in recent years, primarily against Taiwan, Vietnam, India, and the Philippines. Though recent developments have seen the People’s Liberation Army (PLA) of China grow into a highly capable Anti Access/Area Denial (A2AD) force. As a consequence, China is now more likely to co-deploy lower-level military means of expressing disapproval, exerting overt pressure, or countering perceived threats–particularly from the U.S. and its allies in the East and South China Sea. Such measures include sophisticated naval exercises that mimic the blockade of the Taiwan strait, increasingly aggressive flyovers or patrols close to and entering Taiwanese airspace and, most recently, the drills of joint precision strikes on Taiwan, like the “United Sharp Sword” exercise from April 2023.

To sum up, it's not only the terminology and narrative that varies across nations, but also the understanding of what is considered "below the threshold" of conventional warfare. The perception and understanding of grey zone activities play a crucial role in determining their significance and threat level, and critical thresholds are never truly rigid, and may shift depending on domestic politics, threat perceptions, and levels of risk aversion.

The Nuclear Connect

The shifting landscape of global politics has not only brought strategies such as hybrid threats and grey zone warfare back to the foreground of discussion but has also necessitated a pressing re-examination of nuclear issues. As the geostrategic attention pivots from West to East, America's prolonged conventional military superiority has possibly acted as a catalyst for both Russia's and China's moves toward means of non-conventional grey zone methods and an emphasis on nuclear modernisation. Just as there is an overlapping and ambiguity surrounding the boundaries of grey zone warfare, a parallel hazardous confusion is emerging between conventional and nuclear warfare. This is perceptible not only in the increasing deployment of grey zone-style tactics but also in the prominence of dual-use systems, and the co-location of nuclear and conventional weaponry, aiming to enhance ambiguity.

Both the grey zone and nuclear warfare circumvent the domain of conventional warfare. It is therefore not surprising that the most influential grey zone actors in recent years - Russia and China - are also nuclear powers. Russia, a nuclear peer of the U.S., has devoted the 2000s to modernising and diversifying its nuclear arsenal to achieve tactical nuclear superiority over U.S. forces. Meanwhile, China, an economic rival of the U.S., has forsaken its longstanding commitment to minimal deterrence and is rapidly accelerating its own nuclear modernisation efforts.

These developments could suggest a complex intertwining of grey zone tactics and nuclear strategies. The implications of this are significant and necessitate further investigation to fully understand the new realities of global security. The emergence of a multifaceted warfare environment marked by ambiguity–both in the grey zone and in the realm of nuclear capabilities–warrants a comprehensive revision of our understanding of security threats, deterrence mechanisms, and the intricacies of tactic and strategy, as well as their relation.

A Look Towards the Future

As we grapple with the intricacies of tumultuous international relations, the future trajectory of grey zone activities–defined by their inherent ambiguity, deniability and induced passivity when it comes to responding effectively–presents a mix of (de-)escalation strategies. Formulating effective strategies to maintain stability becomes pivotal in such a scenario, as, in the wake of the fast-evolving “hybrid” facet of warfare, grey zone activities are adept at challenging established security architectures, further undermining already fragile (nuclear) deterrence frameworks. The population and popularisation of the grey zone is creating another layer of complexity, steadily reshaping the exercise and contestation of power. Establishing criteria to assess the severity of grey zone tactics and develop a hierarchical risk-based framework for response could streamline the management of such threats. Prioritising investments in intelligence, surveillance, and reconnaissance infrastructure, along with enhancing regional cyberdefence capabilities, can enhance situational awareness, and better attribute activities to specific actors. In the same vein, as technological advancements transform the nature of grey zone tactics, they too, may empower the perpetrators, but also offer potential solutions to combat such threats. Innovations in cyber defence, artificial intelligence, analytics, and machine learning can aid in detecting and neutralising grey zone activities. Cyber-attacks on critical infrastructure or disinformation campaigns can have global implications but may very well be mitigated with capable technological defences in place.

Great powers are increasingly leveraging grey zone activities to shape power dynamics on the world stage. While these actions often target the most transparent political and economic systems–i.e., democracies and open markets–, the growing exchange of information brought about by a globally hyperconnected environment could also serve as a potent deterrent for grey zone activities due to the increased risk of detection. Countering grey zone threats thus necessitates a collaborative, informed, and long-term strategic approach. Engaging in dialogue on grey zone scenarios with key allies and partners can illuminate these concerns and aid in devising capable counterstrategies. Furthermore, evolution in international norms and laws to define and penalise such actions could potentially shape the development of grey zone activities.

However, the complex nuclear landscape marked by multiple great powers with sizable, and growing, nuclear arsenals and varying perspectives on nuclear strategy adds another ever present shade of complexity to this issue. Russia's substantial non-strategic nuclear arsenal and China's recent ICBM silo expansion underscore the evolving–more so deteriorating–nuclear dynamics, as we move onto the Third Nuclear Age. Thus, comprehending and countering grey zone threats must also factor in this broader context of shifting power dynamics and nuclear arsenals.

The grey zone, characterised by its complexity and constant evolution, will continue to shape the future of warfare and international relations. As we chart our course through this uncertainty, understanding the grey zone, its tactics, implications, and devising the necessary countermeasures becomes increasingly critical.