Background: Following 2025's failed negotiations, the US-Israeli military operation Epic Fury on 28 February 2026 marked a sharp escalation against Iran's nuclear and military infrastructure and leadership through a major regional force build-up. Methodology: The study employs a legal doctrinal method, utilizing Article 8 bis of the Rome Statute, the Caroline Test, and International Humanitarian Law (IHL). Objectives: To determine whether the operation constitutes a crime against peace, and whether actions against Supreme Leader Ali Khamenei were valid under IHL. Findings: Khamenei's religious office offered no immunity: Article 110 of the Iranian Constitution vests operational command in him, meaning he exercised a continuous combat function and was a lawful target under jus in bello. However, regarding jus ad bellum, Operation Epic Fury constitutes an act of aggression and lacks justification as anticipatory self-defense, as a multi-week breakout time fails the imminence test while diplomacy remains open. A lawful target struck during an unlawful war remains a casualty of that unlawful war. Originality/Novelty:This study connects “nuclear latency” with the causal theory of imminence and extends shared state responsibility to a decapitation strike against a sovereign leadership fusing religious, political, and military authority.