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.