The 2026 war by the United States and the Zionist regime against Iran took place not only in the military arena but also at the discursive and interpretive levels, turning social media into an important environment for the representation of threat, identity, and legitimacy. Despite the expansion of studies on digital political communication, Trump’s discourse, and political polarization, the existing research gap in explaining how discursive structures, social cognition, and power relations are simultaneously interconnected in the direct communication of political leaders during an international conflict still persists. The present study was conducted with the aim of analyzing how Iran, the United States, war, threat, legitimacy, and political identity are represented in Donald Trump’s messages on the Truth Social platform. The research method is qualitative and based on Critical Discourse Analysis using van Dijk’s socio-cognitive approach, and examines 123 of Trump’s posts about Iran at the macro-semantic, micro-semantic, stylistic, argumentative, and intertextual levels. The findings show that Trump’s discourse creates a coherent pattern of ideological polarization through positive self-presentation, negative other-presentation, and the mitigation of the negative aspects of the ingroup and the positive aspects of the outgroup, and formulates power, threat, and legitimacy at the socio-cognitive level through evaluative vocabulary, presuppositions, agency structures, and modality. Three categories were also identified as intermediate-level composite patterns: “fluid authority,” in which the stability of the leader’s position and identity is combined with the variability of positions and the definition of the enemy and ally; “paradoxical ultimatum,” which formulates a threat of hard action simultaneously with a claim of willingness to avoid such action and the transfer of responsibility for the consequences to the other side; and “discursive management of failure,” which transforms failure from “defeat” into a narrative compatible with the leader’s authority through redefining the objective, claiming precedence, and raising future threats. The main contribution of the article to the study of digital political communication is to demonstrate that van Dijk’s model can explain the connection between ideological polarization, the personalization of political agency, and the production of interpretive authority in leader-centered and multi-audience communication.