The Syndrome
In 1982, Yehoshafat Harkabi published a book that should have been a vaccine. Harkabi had served as head of Aman, Israel’s military intelligence directorate, from 1955 to 1959. After leaving the service he became a professor of international relations at the Hebrew University of Jerusalem, and from that quieter room he produced The Bar Kokhba Syndrome, a study of the revolt that Bar Kokhba led against Rome in 132 CE. Rabbi Akiva had declared Bar Kokhba the Messiah. The narrative replicated. It overrode strategic calculation, suppressed dissenting assessment, and drove a people into a war that destroyed Jewish national life in Judea for nearly two millennia. Harkabi, the intelligence officer, recognised what he was looking at: a self-replicating idea that had consumed its host. He called it a syndrome. A biologist would call it a virus.
A year later and half a world away, at the University of Southern California, a doctoral student named Fred Cohen demonstrated that a self-replicating computer program could propagate through any connected system. His advisor, Leonard Adleman, named the phenomenon a “virus.” Four years after that, Cohen demonstrated that no algorithm could perfectly detect all such viruses. The problem was formally undecidable. Two impossibility results, from Jerusalem and Los Angeles, within a year of each other: Harkabi’s, that a nation cannot reliably immunise itself against its own myths; Cohen’s, that a network cannot reliably immunise itself against self-replicating code. Four decades on, the two impossibilities have converged. The myth now travels as code.
Generative AI has altered the economics of what NATO calls cognitive warfare. A state actor in 2016 needed human operators, cultural knowledge, and language skills to craft locally persuasive disinformation. A state actor in 2026 needs a foundation model and a prompt. The cost of producing a culturally adapted, emotionally calibrated cognitive payload has collapsed by orders of magnitude. What Peter Pomerantsev has called “censorship through noise” now operates at machine speed. A single foundation model can generate persuasive text in any register, synthetic faces increasingly difficult for non-experts to distinguish from authentic footage, and personalised content calibrated to the psychological profile of an individual target. Harkabi’s syndrome required a charismatic leader and a willing population. Its engineered successor requires neither. This is gain of function applied to narrative: the same dual-use risk that haunts virology, transposed to the information domain.
Israel understands this landscape from both sides of the ledger. The country faces cognitive operations on every front: synthetic footage of military operations circulated within minutes of the events they purport to depict, AI-generated testimonials attributed to sources that do not exist, deepfake audio capable of being timed to coincide with diplomatic negotiations. The attacker’s economics are those of a real options portfolio: maintain a diversified inventory of narratives at low individual cost, and exercise whichever option the news cycle renders profitable. The defender’s economics are those of continuous surveillance across the entire information environment, at a cost that scales with the surface area of the threat. The asymmetry is structural, and it widens with each advance in generative capability.
But Israel is also a producer. Every state that maintains an active strategic communications apparatus is, at the operational level, engaged in the same practice it condemns when conducted by adversaries. Harkabi would have recognised the pattern. The distinction between hasbara and cognitive warfare is not a distinction of method. It is a distinction of branding. The syndrome he diagnosed was not a foreign pathogen. It was an endogenous one.
The distribution of impact in cognitive warfare is fat-tailed. Most operations produce negligible effect. A small number produce consequences grossly disproportionate to their cost. The deepfake audio released during Slovakia’s 2023 election media blackout cost virtually nothing and may have shifted the information environment of a European democracy at the moment it was least able to respond. For Israel, a single well-timed synthetic video during a military operation could alter international coalition dynamics within hours, before any verification is possible. The tail is where the strategic consequences accumulate, and Israel lives in the tail.
Cohen’s theorem tells us that perfect detection is impossible. Watermarking and provenance standards address the subset of cases in which the producer cooperates, and leave untouched precisely the cases that matter most. If perfect immunity cannot be achieved, the objective shifts from prevention to resilience: media literacy, institutional trust, rapid-response verification, platform transparency, and coordination between military, diplomatic, and civilian information systems.
Harkabi’s own prescription was simpler and harder. He argued that the most dangerous cognitive virus is the one a nation tells itself, and that the only effective countermeasure is the willingness to examine one’s own narratives with the same rigour applied to the adversary’s. He called himself a Machiavellian dove. He received the Israel Prize in 1993. He died in Jerusalem the following year.
The fortress at Betar, where Bar Kokhba made his last stand in 135 CE, has been empty for nineteen centuries. The narrative that filled it has not. It has been engineered.