Introduction

The Strait of Hormuz is a narrow body of water between the states of Iran and Oman. Besides serving as the only traversable entrance to the Persian Gulf, the Strait is also the world’s most important trade chokepoint. One fifth of the world’s oil passes through the Strait, which means that states are keen on preserving stability in the region, ensuring that their trade is protected and oil prices around the world are stable. The United States (US) has bases in multiple states bordering the Persian Gulf, which makes the Strait of Hormuz a vital passage for the US Navy.

One of the first missions of the US Navy following independence was to protect US commercial vessels in the Atlantic and the Mediterranean from maritime threats. In 1812, a major reason for the US going to war was to ensure the freedom of the rights of trade and commerce across seas and oceans. In 1918, this principle was also staunchly advocated for by US President Woodrow Wilson in his famous ‘Fourteen Points’ speech. These key moments in US history along with the fact that since 1979, the ‘Freedom of Navigations Program’ (FONOPS) has been formally active, highlights that the US has a significant interest in acting to protect the freedom of navigation. China, against whom a majority of US FONOPs have been more recently directed, has asserted repeatedly that such actions by the US violate Chinese sovereignty.

This leads to the broader question of how such operations should be viewed under international law. A context where this question is particularly salient is the Strait of Hormuz, which is a potential site for US FONOPs due to the recent escalation of tensions between the US and Iran. This report analyses the rights of transit and innocent passage of US Navy ships and argues that such passage is permissible under international law despite Iranian requests for prior authorisation or notification. To that end, this report lays out the relevant provisions of international law that are applicable in this context and draws mainly from the judgement of the International Court of Justice (ICJ) in the Corfu Channel case of 1949.