In 2024, there was a notable rise in allegations of non-kinetic hybrid threats originating from state actors. Cognitive warfare —the manipulation and weaponisation of the human mind—particularly gained prominence as a potent tool in international politics and competition for power. NATO has described it as the 21st-century game changer, and a potential sixth warfighting domain in addition to land, sea, air, space, and the cyber domains.
The growing interest in human cognition as a domain of warfare signals a departure from past characterisations of cognitive manoeuvres as mere conflicts short of war. This shift underscores an urgent need for clarity on (i) which actions in the cognitive domain constitute prohibited use of force under Article 2(4) of the UN Charter, and (ii) what threshold such actions must meet to constitute prohibited force. This post explores these critical questions.
Defining Cognitive Warfare
The NATO alliance defines cognitive warfare as activities conducted in synchronisation with other instruments of power to affect attitudes and behaviours, by influencing, protecting, or disrupting individual, group, or population level cognition, to gain an advantage over an adversary. China’s “Three Warfares” strategy, which encompasses public opinion warfare, psychological warfare, and lawfare is often cited as a quintessential example of cognitive warfare.
However, while Cognitive warfare overlaps other non-conventional and non-kinetic types of warfare/operations, it is ultimately unique in its execution and purpose. Destabilisation and influence are the fundamental goals of cognitive warfare.
Bernal et al. (2020) distinguish cognitive warfare from information warfare by emphasising their distinct objectives: while information warfare focuses on controlling the dissemination of information, cognitive warfare strategically aims to control or alter the way people react to information. They define cognitive warfare as the weaponisation of public opinion, by an external entity, for the purpose of (1) influencing public and governmental policy and (2) destabilising public institutions.
Cognitive warfare harnesses communication platforms such as social media and related cybertechnologies such as algorithms and automated software (e.g., bots or trolls) to systematically profile populations, manipulate their cognitive biases, and subtly influence their cognitive behaviour. The weaponisation of neuroscience notably adds a layer of complexity and sophistication to cognitive warfare. Serious concerns have been raised about possible pharmaceutical enhancements and biological and therapeutic emotional manipulation through Transcranial Direct-Current Stimulation, Brain-Computer Interfaces, and Gene editing for hostile purposes (Wheelis and Dando, 2005; DeFranco et al., 2020; Lubell & Alkhateeb, 2022).
Across these different dimensions, the disruptive and destructive potential of cognitive warfare is undeniable. It presents unprecedented opportunities for violence, coercion, repression and subjugation, which if unregulated would radically alter the nature conflict.
Prohibited Force in Cognitive Warfare
The prohibition of the use of force is enshrined in Article 2(4) of the United Nations Charter which mandates that “[a]ll Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the purposes of the United Nations.”
Traditionally, prohibited force under Article 2(4) has been interpreted as military attacks involving physical force (Farer 2017; 79). Non-physical coercive acts, and forcible acts which occasion no physical harm or destruction have severally been rejected as a form of ‘force’ falling under Article 2(4), even when they threatened the territorial integrity or political independence of a State (Pobjie 2024; 116). Pursuant to this interpretation, cognitive warfare is often classified as mere covert operations or conflicts below the threshold of armed conflict due to its non-kinetic nature, and the supposition that its most immediate effects are purely psychological, and not physical.
Such classification, however, fails to appreciate the lethal capabilities of cognitive warfare.
While non-kinetic, cognitive operations are becoming a dominant dimension of lethal conflicts, with a direct causal link to physical harm. In the Isreal-Gaza war and the Ruso-Ukrainian war, for instance, cognitive tactics have been instrumental in mobilising public and military support for the execution of war crimes and forceful acquisition of territory. In the US, cognitive operations aimed at decaying trust in electoral systems led to significant political and social unrest, that culminated into a deadly insurrection. Other notable examples include “Operation Mass Appeal”, and the systematic “Iraq’s weapons of mass destruction” campaign to rationalise the 2003 invasion of Iraq, to mention just a few.
Owing to its subtlety, cognitive warfare can be woven into any conflict environment to induce intensity and lethality. Successful cognitive operations can have profound destabilising effects akin to kinetic armed conflicts. They can incite social unrest leading to the damage of critical infrastructure, disrupt essential services, dehumanise and desensitise a population to commit genocide, and legitimise colonialist campaigns that erode political independence and territorial integrity of a state.
The emerging consequence-based approach centres these effects as opposed to the methods used to cast various cognitive operation as prohibited uses of force.
The Consequence-Based Approach
The consequence-based approach postulates that while prohibited force in article 2(4) applies to physical force, it is the effects of a ‘use of force’ that are likely to be decisive in its characterisation as such, and not physical means or kinetics (Pobjie 2024; 116). A combination of thresholds including intention, physical harm, sufficient proximity, and severity, are required for an act to constitute prohibited use of force under the approach.
Severity
The scope, duration, and intensity of the harm occasioned by a cognitive attack has great bearing on the appraisal of such attack as constituting a use of force under Article 2(4). This threshold reflects the scale and effects standard adopted by the ICJ in the Oil Platforms Case (2003) to distinguish an armed attack from a mere frontier incident. Pursuant to this test, the scale and effects of a cognitive operation must reach the threshold of an “armed attack” for it to qualify as prohibited use of force.
Interpretations of Article 51 of the UN Charter have qualified an armed attack as use of force involving substantial destruction of property, loss of life, or injury. Thus, cognitive operations that cause physical harm to people and property are likely to fall within the scope of prohibited force. An example could be a cognitive operation that manipulates public sentiments to decay trust in an electoral process, leading to a constitutional crisis, riots, destruction of property and loss of lives such as was the case in the US Capitol riots of 2021.
It’s worth noting however, that minor or less disruptive cognitive attacks that involve brief or periodic interruption of non-essential services with no significant physical damage, are less likely to be considered prohibited force. This exception, while rational, creates a loophole where repeated minor operations could cumulatively cause harm without legal repercussions.
Physical harm
There is a broad consensus that a forcible act that targets or causes damage to something other than a person or an object is likely to fall outside the scope of prohibition. Pobjie argues that while there is nothing explicit in the text of article 2(4) itself that restricts its scope to physical harm or harm to certain objects, non-physical effects alone (such as psychological, economic or more abstract forms of harm) are not likely to be legally relevant to the determination of whether an act is a ‘use of force’. The effects of a cognitive operation must therefore involve physical harm to individuals or property for it to meet the threshold of the use of force.
Meeting the evidentiary standards of this threshold could be difficult, especially proving that a particular cognitive operation is directly responsible for the physical harm. The scope of the threshold also leaves a legal and operational gap in addressing “grey zone” tactics that fall short of causing physical harm yet still undermine sovereignty and stability. These limitations may generally undermine the ability for international law to adequately protect international peace and security in this epoch of cognitive warfare.
Proximity
For the physical harm threshold to be met, there should be a direct causal link between the cognitive act and the physical harm. There must be no intermediate steps between the action and its result. This criterion ensures that the harm is not too remote or indirectly linked to the operation. This, however, should not be interpreted to mean that the harm must be instantaneous, because effects in cognitive operations often emerge over time. A cognitive operation that triggers delayed but unavoidable and substantial harm could therefore still meet the threshold if the causation is direct. What matters is that the effects are predictably tied to the action and occur within a timeframe that reflects a foreseeable progression of harm.
A good example could be “operation gridlock” against “excessive quarantine measures”. Which, while it cannot be classified as an effect of a cognitive operation, shares elements of one – how modern information ecosystems can create significant (often delayed) social disruptions. The operation, a result mostly of manipulation of cognitive biases, had the potential to cause critical infrastructure failures and significant public health crises.
It is worth noting that an operation with immediate but indirect consequences might not satisfy the requirements of prohibited use of force unless the effects closely resemble the physical consequences typically associated with force State (Pobjie 2024).
Intention
Finally, intention, while not an established threshold plays a critical role in distinguishing between accidental harm (e.g., collateral damage) and deliberate use of force. Unintended consequences arising from acts analogous to cognitive attacks are not likely to be legally relevant to the determination of whether a cognitive attack is a ‘use of force’. An example here is when Facebook’s algorithms inadvertently amplified and promoted content which incited hatred, discrimination, and violence against the Rohingya and the Tigrayan community in Mayanmar and Ethiopian, respectively.
Were such violence to accrue from a purposeful manipulation of Facebook algorithms by another state, or a non-state actor under the direction or effective control of another state, with a clear intention to destabilise or exploit these conflicts, then such acts could have fallen in the scope of prohibited use of force, provided other thresholds were equally met.
Intent can be determined by the gravity of an attack. The minor nature of an attack is more likely to be interpreted as prima facie evidence of absence of intention to attack, or of a honest mistake, or simply the limited objectives of an attack (Brownlie 1963; 365). Conversely, a cognitive operation of a severe intensity could be treated as an indicator of intention. The combined threshold of gravity and intention is also critical in determining when a military response can be employed in self-defence against an offensive cognitive attack. In this case, Brownlie notes; “…when the justification of self-defence is raised the question becomes one of fact, viz., was the reaction proportionate to the apparent threat?”
Conclusion
The proliferation of cognitive warfare in international politics presents unprecedent challenges for international law. While it does not completely operate in a legal vacuum, it occupies a delicate grey-zone that could easily escape international law regulation. Reassessment of the thresholds for what constitutes prohibited use of force under international law is therefore needed to address the unique characteristics of cognitive warfare. The consequence-based approach, which has also been unanimously adopted in the context of cyber warfare, presents a viable framework for a redefinition of use of force to encompass the non-kinetic yet highly destructive actions in the cognitive domain. The framework, however, needs refining to address blind spots that could allow the deployment of destructive technologies without culpability, such as regards the qualification of the severity, proximity, and physical harm thresholds. Without clearer watertight thresholds, Article 2(4) of the UN Charter risks losing its prohibitory power in the face of modern conflict, leaving a dangerous void in safeguarding sovereignty, stability, and international peace.
