This study investigates the mechanisms favoring the adoption of antagonistic policies towards Iran in the United States, focusing on the roles played by Israel and pro-Israel actors in these processes. Based on the combination of literatures from different fields such as nationalism, security studies, narratives and sociology, the proposed argument posits that the constant identification of US policymakers as pro-Israel creates conditions that favor the (re)production of an antagonistic identification of Iran and subsequently delimits the spectrum of viable policy options. In particular, the proactive efforts of Israel and pro-Israeli actors in the US to establish that "being pro-Israel" is intrinsically synonymous with "identifying Iran in an antagonistic and threatening way" place US policymakers before a binary choice: either you're with Israel against Iran, or you're with Iran against Israel. The possibility of simultaneously supporting Israel and advocating a conciliatory approach to Iran is out of the question. Given the dominance of the pro-Israeli identification within the American political field, anyone deviating from the antagonistic identification of Iran would be perceived not only as anti-Israeli, but also as anti-American. These opposing but related dynamics of association and dissociation, supported by Israel and pro-Israeli actors, are shaping the American decision-making environment with regard to both Iran and Israel.