The Limits of Plausible Deniability in Ukraine and Beyond

Drone strikes targeted Moscow last week. Though much remains unknown about it, the episode appears to be part of a series of unclaimed coercive attacks that US officials attributed to Ukrainian government personnel, including the killing of the daughter of a Russian nationalist, the sabotage of the North Stream pipelines, and drone attacks on the Kremlin.

With unclaimed coercion, perpetrators impose costs on adversaries to signal their resolve to prevail in disputes while denying involvement or simply not making any claim about responsibility. Unclaimed coercion is not unique to the war in Ukraine. Russia launched cyber attacks in 2007 to extract concessions from Estonia, though Moscow denied responsibility, and in 2010 Seoul claimed North Korea torpedoed a South Korean warship, Pyongyang’s denial notwithstanding.

Unclaimed coercion may have strategic benefits. Without unmistakable evidence about the identity of the perpetrator, the absence of a claim of responsibility creates plausible deniability, which, some argue, allows coercers to send intelligible, credible messages to targets while containing escalation risks. It may also reduce the costs of being seen as a norm violator. For instance, Austin Carson observed that, though both Saudi Arabia and the United States viewed the 2019 attacks on Saudi oil facilities as part of an Iranian coercive campaign, the absence both of conclusive evidence and a claim of responsibility prevented Riyadh and Washington from carrying out a tough military response, which would have looked “illegitimate while jeopardizing allies’ support.”

But there may also be drawbacks.