A closer analysis of the tensions in the Eastern Mediterranean demonstrates that while Article 42(7) could, theoretically at least, be an important tool for deterrence, practically it may have an inadvertent negative impact. Namely, it could potentially push aggressive and revisionist states to engage in hybrid hostile actions that lead to instability and the development of grey areas, without however crossing the threshold of what would be seen as armed aggression. This brief article explores why this is the case and why Article 42(7) TEU is a useful, albeit insufficient, ‘deterrence tool’ for the RoC and Greece for dealing with the tensions in the Eastern Mediterranean.