War and Power in the Twenty-First Century: Decision-Making Architecture and Legitimacy in United States War Policy

The Case of Iran in a Transforming International System

Abstract

This article examines the contemporary model of war decision-making in the United States through the case of the conflict with Iran and its political, institutional, economic, geopolitical, and social implications. The study is based on the premise that war in the twenty-first century can no longer be understood solely as a military or presidential decision, but rather as a complex process of constructing and sustaining legitimacy, simultaneously conditioned by domestic and external factors. Throughout the study, the article analyzes the fragmented architecture of the U.S. decision-making system, in which executive authority, legal constraints derived from the War Powers Resolution, the role of Congress, the influence of the national security apparatus, public opinion pressures, and the dynamics of international alliances converge. The analysis demonstrates that, although the Executive Branch retains broad operational capacity to initiate military action, the political sustainability of a conflict depends on the continuous interaction among domestic legitimacy, strategic coherence, and public perceptions regarding the costs of war. The article also examines the role of political language and narrative construction in contexts of conflict. It argues that the legitimacy of war is not a permanent resource, but rather a political asset that must be continuously reconstructed through narratives aimed at justifying intervention, containing domestic erosion, and preserving cohesion among strategic allies. In this sense, political discourse does not merely describe the reality of conflict; it actively contributes to structuring it. The study also addresses the role of allies within the architecture of strategic decision-making, demonstrating that contemporary alliances function less as automatic mechanisms of military obedience and more as flexible systems for aggregating sovereign decisions. The case of the conflict with Iran reveals growing tensions within the Western bloc, particularly between the United States and certain European allies, whose perceptions regarding the risks, costs, and objectives of the conflict do not always fully converge.