Iran closed the Strait of Hormuz in response to February-March 2026 strikes, restricting approximately 20% of the world's oil and liquefied natural gas transit and causing global oil prices to soar

For: Iran has blocked almost all shipping through the strait

• Iran's strategic objective in the war is economic coercion by endurance through control of the Strait of Hormuz and attacks on energy infrastructure, not a classic military victory. Iran's near-total closure of the strait through military control directly serves economic coercion and endurance rather than achieving classic military victory on the battlefield. 4 sources, analysis
• Iran asserts control over the Strait of Hormuz. A 94% decline in merchant traffic enforced by Iranian military assets since late February 2026 directly demonstrates Iran's operational control over the strait, which is the core claim. 1 source, editorial
• Iran has maintained operational control and enforcement of the Strait of Hormuz since February 28, 2026. Iran's military assets and the 94% decline in crossings since February 28 confirm operational control and enforcement of the strait continues through March 19. 1 source, unnamed sources
• Iran's control over the Strait of Hormuz represents a significant economic and geopolitical leverage over global shipping and oil trade, given the strait's role as a vital global shipping route and Iran's demonstrated willingness to restrict traffic. The 94% decline in crossings and Iran's military enforcement since February 28 show Iran now controls access to a vital global energy route, confirming its leverage over shipping and oil trade. 1 source, analysis
• Iran's effective closure of the Strait of Hormuz in response to 28 February 2026 strikes demonstrated military effectiveness in escalating economic pressure on the United States and global economy. A near-total closure of shipping directly demonstrates the military effectiveness and economic pressure that the proposition claims—the 94% decline in crossings shows Iran's capability to enforce control and impose significant disruption. 1 source, analysis

For: Iran is letting some ships through based on which country owns them

• Iran's strategic objective in the war is economic coercion by endurance through control of the Strait of Hormuz and attacks on energy infrastructure, not a classic military victory. Selective passage based on nationality allows Iran to pursue long-term coercion and political concessions while avoiding universal economic damage that could force escalation. 4 sources, analysis
• The pattern of selective vessel passage through the Strait of Hormuz demonstrates Iran's ability to differentiate between flags and nationalities of ships, allowing friendly nations passage while potentially restricting others. Explicit pattern of flag-based and nationality-based vessel differentiation directly confirms Iran's ability to enforce selective passage as the core claim of this hypothesis. 2 sources, named source
• Iran's restriction of Strait of Hormuz passage represents a precedent for conditioning access to key maritime chokepoints on political relationships rather than established norms of open transit. Iran's explicit selectivity by flag and nationality—allowing friendly nations passage while restricting others—directly establishes a precedent for conditioning chokepoint access on political relationships. 1 source, analysis
• The Strait of Hormuz closure is unprecedented in modern history and could prolong if Iran targets all transiting ships. Allowing some ships through based on nationality contradicts an unprecedented total closure; selective passage keeps options open for future escalation if targeting all transits. 1 source, named source
• Iran's decision to selectively close the Strait of Hormuz represents a coordinated geopolitical strategy to isolate Western-aligned states while strengthening ties with non-aligned powers. Selective closure allowing friendly nations passage while restricting western-aligned states directly demonstrates the coordinated geopolitical strategy to isolate some powers and strengthen ties with others. 1 source, analysis

For: It's unclear if Iran is blocking everything or just some ships

• Iran demonstrated the strategic and operational capability to strangle the global economy by closing the Strait of Hormuz. Demonstrated strategic and operational capability to close the strait confirms the core of the ambiguity hypothesis: Iran has the ability to take either total or selective action. 1 source, analysis
• Any commercial ship attempting to transit the Strait of Hormuz without Iranian approval faces risks that constitute a nightmare scenario for maritime operators as of March 19, 2026. The nightmare scenario for operators—uncertain whether passage is possible—directly embodies the ambiguity hypothesis about unclear blockade scope. 1 source, named source
• The Strait of Hormuz closure is unprecedented in modern history and could prolong if Iran targets all transiting ships. The ambiguity hypothesis matches a scenario where Iran could target all ships indiscriminately and precedent is therefore unprecedented and open-ended. 1 source, named source

Supporting evidence

• Iran asserts control over the Strait of Hormuz. Iran's assertion of control over the Strait of Hormuz—demonstrated through selective passage and toll-system demands—directly supports the temporary negotiating tool hypothesis by showing Iran has achieved operational leverage it can use as pressure in talks. 1 source, editorial
• Iran's effective closure of the Strait of Hormuz in response to 28 February 2026 strikes demonstrated military effectiveness in escalating economic pressure on the United States and global economy. Iran's demonstrated closure of the Strait following the February strikes directly shows the blockade is operationally effective and tied to immediate military escalation, supporting the view that it functions as pressure rather than permanent repositioning. 1 source, analysis
• Iran has demonstrated that it possesses proven capacity to coerce the global economy via closure of the Strait of Hormuz. Proven capacity to coerce the economy via blockade is the foundational capability required for a blockade to function as negotiating leverage. 1 source, editorial
• Iran has credible ability to control the Strait of Hormuz as leverage in negotiations. Iran's demonstrated control and selective passage directly prove the blockade capability needed for coercive leverage in negotiations. 1 source, analysis
• Iran's blockade of the Strait of Hormuz represents the most significant asymmetric lever available to Iran for imposing disproportionate costs on the United States and allies. The proposition establishes the blockade as Iran's highest-leverage coercive asset, exactly matching the temporary-tool hypothesis's core mechanism. 4 sources, analysis

For: Long blockade means high prices for years

• Iran's strategic objective in the war is economic coercion by endurance through control of the Strait of Hormuz and attacks on energy infrastructure, not a classic military victory. The proposition states Iran's objective is economic coercion through strait control, the core mechanism by which this hypothesis predicts years of high prices. 4 sources, analysis
• Iran's effective closure of the Strait of Hormuz in response to 28 February 2026 strikes demonstrated military effectiveness in escalating economic pressure on the United States and global economy. Iran's sustained closure demonstrates military capability to inflict economic damage; this reading of 'effectiveness' requires blockade persistence, which this hypothesis predicts. 1 source, analysis
• Iran's control over the Strait of Hormuz represents a significant economic and geopolitical leverage over global shipping and oil trade, given the strait's role as a vital global shipping route and Iran's demonstrated willingness to restrict traffic. The proposition directly states Iran's blockade gives it leverage over global shipping and energy trade—exactly what this hypothesis requires for sustained high prices. 1 source, analysis
• Iran's demand for control over the Strait of Hormuz and toll systems suggests that Iran intends to use the blockade as leverage for long-term political and economic concessions beyond the current conflict. Iran's demand for toll control and long-term concessions directly indicates intent to maintain the blockade as leverage, the operational foundation for years of elevated prices. 6 sources, named source
• The Strait of Hormuz blockade represents Iran's highest-leverage negotiating tool given its control over 20 percent of global energy supplies. The proposition identifies the blockade as Iran's highest-leverage tool controlling 20% of global oil supplies, directly supporting why Iran would maintain it long-term for high prices. 1 source, analysis

For: Markets adapt quickly, prices return to normal

No strong supporting evidence

For: Military or diplomacy ends blockade in months

No strong supporting evidence