Analysis of the Legal-Political Requirements for Iran's Blockade of the Strait of Hormuz in the Gray Zone Warfare with Israel

Introduction
The Strait of Hormuz, as one of the world's most critical energy chokepoints, holds significant strategic and symbolic importance in the security of the Middle East. In the context of the ongoing gray zone warfare between Iran and Israel—a domain situated between peace and all-out war, characterized by proxy operations, cyberattacks, and diplomatic pressure—the threat to close the Strait has emerged as a key deterrent tool in Iran's foreign policy. This study examines the legal and political requirements for employing this tool, addressing the question: What prerequisites must be met for a threat or action to block the Strait of Hormuz, within the framework of gray zone warfare, to be legitimate, effective, and low-cost?
Methods
This qualitative research, applied-developmental in nature, employs a descriptive-analytical approach. It draws on primary sources (including UNCLOS, the UN Charter, and the San Remo Manual) and secondary sources (specialized books, articles, and think tank reports) through documentary analysis.
Results and Discussion
The conceptual framework integrates deterrence theory, concepts of gray zone or hybrid warfare, the law of the sea, and the political economy of energy. The findings confirm that the successful use of a blockade as a deterrent depends on four interrelated conditions:
International Legal Requirements: The transit passage regime under the Law of the Sea Convention prohibits unilateral blockades. The only viable justification is self-defense under Article 51 of the UN Charter, which requires proof of an armed attack or imminent threat, adherence to the principles of necessity and proportionality, and reporting to the Security Council. The legal framework for maritime blockades (e.g., the 1994 San Remo Manual) imposes additional strict conditions, including formal declaration, effectiveness, and compliance with humanitarian obligations. The Corfu Channel case further emphasizes the duty of the coastal state to provide warnings and prevent navigational hazards. Given Iran’s non-ratification of UNCLOS, establishing legitimacy requires meticulous legal documentation and credible evidence of exigent circumstances.
Iran’s Legal Posture: Iran must bridge the gap between its international obligations (including customary law) and its national positions, framing its sovereignty or security claims in internationally acceptable terms.
Political-Strategic Credibility: Deterrence hinges on credible threat signaling. While Iran can cause temporary disruption (via mining, fast-boat operations, or cyberattacks), sustaining a prolonged blockade is logistically challenging and costly, particularly in the face of potential international counter-operations. An effective gray zone strategy involves managing ambiguity—making the threat credible without necessarily acting upon it. This requires unified internal coordination (across government and military bodies) and proactive diplomacy with key energy-importing states (e.g., China, India, and the EU) to prevent the formation of a hostile coalition. Crisis communication channels are essential to avoid unintended escalation.
Economic Safeguards: Disrupting the Strait would impact global energy markets but could also backfire, endangering Iran’s oil revenues and internal economic stability. Therefore, any threat or action must be underpinned by domestic economic resilience, strategic reserves, and alternative revenue plans.
Conclusion
In conclusion, a Hormuz blockade in a gray zone conflict represents a high-risk, dual-edged tool. If all four conditions are met precisely and simultaneously, it can raise the costs for the adversary and function as an effective deterrent. However, the absence of any condition may lead to counterproductive outcomes—undermining Iran’s international legitimacy, provoking a global coalition against it, straining its economy, and shifting the strategic balance to its disadvantage. Decision-making thus requires a holistic perspective, careful cost-benefit analysis, and preparedness for complex consequences.