Originally published at Project-Syndicate | Dec 13th, 2024
Impersonation is one of the oldest tactics in war, because it exploits our social nature and persists because humans are dependent on identities for cooperation. Worse, new technologies now make it possible to mimic faces, skin color, voices, and other features that have long given counterintelligence a fighting chance.
TURIN/OXFORD – Israel’s detonation of thousands of pagers held by Hezbollah fighters and loyalists in mid-September will be remembered as one of the most ingenious plots in the history of spycraft. It is also a reminder that the most powerful weapon in war is not a fighter jet, a drone, or even artificial intelligence, but rather something much older: impersonation.
Central to the Israeli operation was the human infiltration of supply chains. Three years ago, Israel’s intelligence agency, Mossad, developed a custom pager containing plastic explosives. It then sent agents to trick the Taiwanese company Gold Apollo into marketing the device to the right buyers. Thus, Israel’s biggest blow to Hezbollah in 40 years hinged on the simple dynamic of one human persuading another that he was someone else.
Impersonation – or “identity mimicry” as we call it in a recent book on the topic – is a widely used weapon of war. When Russia invaded Ukraine in February 2022, the first Russian convoy headed for Kyiv was disguised as a Ukrainian unit to avoid detection. Male jihadists have dressed as women to pull off suicide bombings so often that several Muslim countries now ban face veils on security grounds. And it is not just Islamists who use this ploy. Earlier this year, Israeli soldiers entered a West Bank hospital dressed as Palestinian women and doctors to kill three suspected militants.
Mimicry also serves many other purposes. Spies routinely use it to steal sensitive information, which is probably why Bulgarians arrested on espionage charges in the United Kingdom last year were in possession of passports from nine different countries. And rogue actors use it to acquire illegal products, as North Korea has done to great effect in its nuclear weapons program.
Mimicry can also allow one to escape captivity, as Colombian drug cartel leader Juan Castro demonstrated when he walked out of a maximum-security jail in 2022 dressed as a guard. And it can be used to distract, as Saddam Hussein did by hiring body doubles to confuse potential assassins. Impersonation is powerful because it is upstream to many other war tactics, making it the master form of deception.
Every day in every conflict zone around the world, fighters and civilians must be on the lookout for impostors, because the consequences of missing one can be devastating. Let the wrong people into your base, and you will be attacked from the inside. Trust the wrong taxi driver, and you can be captured and tortured.
Impersonation is as old as war itself. Mimicry episodes were so frequent in antiquity that the classical authors Frontinus and Polyaenus wrote catalogues with hundreds of examples as a warning to generals. Subsequent periods featured no less of it – from sixth-century Byzantine spies dressing as Persians to infiltrate the Sassanid army to Jews in World War II pretending to be Catholics to escape Nazi persecution.
The phenomenon persists because humans are dependent on identities for cooperation. To trust other people, we need a sense of how they will behave in the future, and reputations help. Mimicry is therefore parasitic on the benefits we derive from honestly signaling our identity. Countering mimicry is difficult because what makes or breaks an impersonation varies by context. The devil is often in the details, which is why British interrogators in WWII sought to weed out suspected German spies by testing their knowledge of pre-war cricket scores.
Some techniques have stood the test of time. The Old Testament Book of Judges relates how the Gileadites sought to identify Ephraimite pretenders by making them say “shibboleth,” a word that an Ephraimite would pronounce with an accent. Fast forward to the start of the Ukraine war, and we find Ukrainians using the word palyanitsya (a type of bread) as a pronunciation test for suspected Russian spies. By now, though, the word has likely lost its probing power. Impersonation is a dynamic affair, with mimics and counter-mimics constantly adapting to each other’s tactics.
Technology can alter the game. A key concept in mimicry research is the hard-to-fake or costly sign. Historically, things like faces, skin color, and voices have been difficult to imitate, so when we saw a video of a politician engaged in lurid activity 25 years ago, we rarely questioned its authenticity.
This has changed with generative AI. Earlier this year, a finance worker in Hong Kong was duped into transferring $25 million after attending a group videocall in which everyone else was synthetically created. Deepfakes have already been deployed for war propaganda, notably in Ukraine, where fake videos of Vladimir Putin and Volodymyr Zelensky proliferate. Reports of operational use remain few, but that is likely to change, for we are entering a golden era of wartime mimicry in which impersonation is a threat no less powerful than the most sophisticated weapons systems.
Diego Gambetta: Chair in Social Science at the Collegio Carlo Alberto in Turin, and an emeritus fellow at Nuffield College, University of Oxford, is the co-author (with Thomas Hegghammer) of Fight, Flight, Mimic: Identity Mimicry in Conflict (Oxford University Press, 2024).
Thomas Hegghammer: A Senior Research Fellow in Politics at All Souls College, Oxford University, is the co-author (with Diego Gambetta) of Fight, Flight, Mimic: Identity Mimicry in Conflict (Oxford University Press, 2024).