Trump wants allies to join naval coalition to open Strait of Hormuz - but no one has agreed yet. Here's why

The geopolitical crisis surrounding the Strait of Hormuz has escalated into a high-stakes standoff. As oil prices surge past $100 a barrel, US President Donald Trump has issued a call for an international naval coalition to forcibly secure this narrow maritime artery. However, despite the potential for global economic instability, the response from the international community has been tepid at best, revealing deep fissures in global security policy and the daunting reality of modern maritime warfare.

Trump’s push for maritime enforcement

President Trump’s strategy relies on the assumption that a show of naval force can neutralise Iran’s capacity to disrupt shipping. His administration has publicly invited China, France, Japan, South Korea, and the United Kingdom to contribute warships. The US rhetoric is dual-tracked: promising "a lot" of support for participating nations while simultaneously threatening NATO members with a “very bad future” if they decline to assist in what the US deems a mission to keep the waterway "open, safe, and free."

Iran’s strategic leverage

Tehran has framed its actions not as a total closure of the strait, but as a selective blockade targeting the US and its allies. By maintaining a presence and leveraging the geography of the waterway, Iran has effectively signalled that the strait is under its functional control. This creates a psychological and physical barrier that, according to Iranian leadership, will remain as long as the conflict with the US and Israel continues. For Iran, the Strait is a primary instrument of asymmetrical warfare, providing a critical lever of power against a superior conventional military force.

The daunting obstacles to naval coalition success

Several critical challenges make a coalition difficult to implement and potentially ineffective:

1. Geographic vulnerability: At just 21 nautical miles wide at its narrowest point, the Strait is an “unforgiving environment.” The proximity of the Iranian shoreline allows for the effective use of land-based missiles, drones, and mines.

2. The interoperability gap: As noted by experts like Alexandru Hudisteanu, coordinating naval units from multiple nations, each with different doctrines, communication protocols, and rules of engagement, presents a massive logistical hurdle.
3. Asymmetric threats: Traditional naval assets - designed for ship-to-ship combat - are often ill-suited to detect and counter the swarming, low-tech, or unmanned systems that characterise current Iranian naval tactics.

4. Escalation risks: For any foreign navy, participating in an escort mission carries the risk of direct kinetic engagement with Iran, potentially drawing those nations deeper into a war they are currently trying to avoid.

International reluctance and diplomatic stagnation

The global response suggests that Trump’s call has failed to generate momentum. France and Australia have explicitly ruled out sending vessels, emphasising a desire to remain out of the direct conflict. Japan is proceeding with extreme caution, balancing its reliance on Gulf energy with a reluctance to commit military assets. While the UK and South Korea have expressed concern and are "monitoring" the situation, none have committed to a military role.