Tariff wars in the last decade have shown that customs tariffs are no longer just traditional instruments of trade policy, but have gradually become a tool for exerting political, economic and security pressure in international relations. This development has raised fundamental questions about the relationship between the economic sovereignty of states, obligations arising from the General Agreement on Tariffs and Trade (GATT) and the effectiveness of the legal system of the World Trade Organization (WTO). The present study, with a descriptive-analytical approach and using library resources, WTO documents, dispute settlement procedures and judicial decisions, examines the legal status of tariffs, the effects of tariff wars on the rules-based order of world trade and the limits of states' reliance on the national security exception of Article XXI of GATT. The findings of the study show that the expansion of unilateral tariff measures and the broad interpretation of the national security exception have undermined fundamental principles such as non-discrimination, predictability, and legal certainty in international trade and have challenged the effectiveness of the WTO dispute settlement mechanism. an analysis of recent US court rulings on the limits of the President’s authority to impose tariffs shows even in domestic legal systems, the tendency to limit the unilateral application of tariffs within the framework of the rule of law has been strengthened. with an emphasis on the situation in Iran, suggestions are presented for aligning tariff policy with accepted principles of international trade law and reducing vulnerability to changes in the global trading system.