["Middle East Policy, EarlyView. ", "\nAbstract\nThe Iran War erupted in February 2026 without UN authorization, and Washington's rationales—Iranian nuclear ambitions, missile capacity, and proxy threats—map more closely onto Israeli than US security interests. Why have we seen two major conflicts between these belligerents in less than one year? This study argues that the Israel‐Iran escalation spiral between 2023 and 2026 followed the logic of an iterated chicken game. Incremental brinkmanship gradually normalized direct conflict, which sparked the 12‐day war of 2025. A ceasefire was reached only after the combatants' calculations were altered by Washington's bombing of Iran's nuclear sites and its forcing Israel to stop short of destroying the regime. However, this left the underlying incentive structure intact, resulting in a far more destructive offensive in 2026. The article contends that the June 2025 collision did not restore deterrence but transformed the conflict into a more volatile US‐Iran confrontation. Israel's escalatory threshold has been lowered as it assumes continued American backing, while Iran's incentives to pursue nuclear breakout have increased. The conclusion lays out steps the United States must take to prevent more devastation.\n"]