This article examines how the Iranian nuclear program was discursively constructed as a security threat by the George W. Bush administration, within the theoretical framework of the Copenhagen School. The study contextualizes the historical rivalry between Iran and the United States and highlights the geopolitical significance of Iran’s nuclear development after the Cold War, particularly regarding regional power balances and global nonproliferation debates. Through a critical discourse analysis of presidential speeches, it identifies how narratives — such as the “axis of evil” and catastrophic imagery — were deliberately employed to justify exceptional measures, including economic sanctions, diplomatic marginalization, and political isolation. The article argues that by portraying the nuclear program as a threat to international order and stability, the U.S. shifted the issue from the political to the security realm, thereby altering both public and institutional perceptions of Iran. It concludes that this securitizing rhetoric supported practices of containment, legitimized unilateral actions, and demonstrated the strategic function of political language in shaping security policymaking and sustaining hegemonic influence