Iran’s Threat to Close the Strait of Hormuz: Context and Significance

On multiple occasions in 2023 and early 2024, Iran’s leadership, particularly the Iranian Revolutionary Guard Corps (IRGC), has threatened to completely close the Strait of Hormuz, a narrow maritime chokepoint connecting the Persian Gulf to the Gulf of Oman and the Arabian Sea. The Strait, only 33 km wide at its narrowest, facilitates transit of approximately 21 million barrels per day (bpd) of crude oil, constituting nearly 21% of the world’s petroleum liquids trade (U.S. Energy Information Administration, 2023). Iran’s threat is a strategic lever amid escalating sanctions and geopolitical tensions, especially with the United States, which maintains a significant naval presence through the U.S. Navy Fifth Fleet headquartered in Bahrain.

The significance lies in Iran’s ability to disrupt a critical artery of global energy supply, exposing vulnerabilities in international maritime governance and energy markets. This threat also highlights gaps in enforcement under international law and the potential for rapid global economic repercussions.

Legal Framework Governing the Strait of Hormuz

The Strait of Hormuz falls under the regime of Part V of the United Nations Convention on the Law of the Sea (UNCLOS) 1982, specifically Articles 34-45, which regulate straits used for international navigation. UNCLOS guarantees transit passage rights, allowing ships and aircraft of all states to pass through such straits without hindrance, even if they lie within territorial waters.

However, UNCLOS lacks explicit enforcement mechanisms to prevent a coastal state from unilaterally restricting passage, especially when invoking national security concerns. The International Maritime Organization (IMO) provides regulatory oversight on maritime safety but does not have enforcement authority to counteract blockades.

Further complicating enforcement, the UN Security Council has passed resolutions on maritime security in the Persian Gulf, but these have often been stymied by geopolitical rivalries. The U.S. International Emergency Economic Powers Act (IEEPA) 1977 enables sanctions enforcement against Iran, but it does not directly address maritime passage rights.

Economic Impact of a Strait Closure

The Strait of Hormuz is a critical chokepoint for global energy supply. According to the U.S. Energy Information Administration (2023), about 21 million bpd of oil transit the Strait, representing roughly 21% of global petroleum liquids trade. Closure would disrupt supply chains, triggering immediate price shocks.

• Oil Price Volatility: The International Energy Agency (IEA, 2023) projects a 10-20% spike in global oil prices within weeks of a closure, exacerbating inflationary pressures worldwide.
• Iran’s Oil Exports: Iran’s exports fell from 1.1 million bpd pre-sanctions to below 0.3 million bpd during peak sanctions (OPEC Monthly Oil Market Report, 2023), limiting its current leverage but increasing its incentive to disrupt the Strait.
• Regional GDP Contribution: Energy exports from the Persian Gulf contribute over $2 trillion annually to global GDP (World Bank, 2023), underscoring the economic stakes.
• India’s Energy Security: India imports approximately 60% of its crude oil via the Strait (Ministry of Petroleum & Natural Gas, India, 2023), making it vulnerable to supply disruptions and price volatility.
• Insurance Costs: Post recent Iran-US tensions, tanker insurance premiums surged by 40%, raising operational costs for shipping companies (Lloyd’s List Intelligence, 2024).

Geopolitical and Security Dimensions

The Strait’s strategic importance makes it a focal point of geopolitical contestation. Iran’s naval capabilities, primarily through the IRGC Navy, enable it to enforce blockades or threaten closure. The U.S. Navy Fifth Fleet operates to ensure freedom of navigation, often engaging in joint exercises with Gulf Cooperation Council (GCC) navies.

Unlike the Strait of Malacca, where Indonesia and Malaysia cooperate with international navies to maintain security, the Strait of Hormuz is heavily militarized and contested. Iran’s unilateral control attempts increase volatility, affecting global energy markets and regional stability.

Comparative Analysis: Strait of Hormuz vs Strait of Malacca

Critical Gaps in International Maritime Governance

UNCLOS guarantees transit passage but lacks robust enforcement mechanisms to counter threats like Iran’s blockade. Coastal states can exploit ambiguities, citing national security to justify restrictions. The absence of a binding multilateral maritime security framework in the Persian Gulf allows Iran’s IRGC naval forces to threaten closure without immediate international legal recourse.

This gap weakens the international community’s ability to guarantee uninterrupted energy flows, especially given the Strait’s narrow geography and high traffic density.

Way Forward: Addressing the Strait’s Vulnerabilities

• Strengthen multilateral maritime security cooperation involving Gulf states, Iran, and external powers under IMO and UN Security Council auspices.
• Enhance legal clarity and enforcement mechanisms under UNCLOS to prevent unilateral closure of international straits, possibly through new protocols or amendments.
• Develop alternative energy transit routes and diversify energy import sources for dependent countries like India and China to reduce vulnerability.
• Expand real-time maritime domain awareness and intelligence sharing to preempt blockades or escalations.
• Promote diplomatic engagement to reduce Iran-US tensions, addressing underlying sanctions and security concerns.