The US Navy and the two naval components of the Iranian armed forces, the Islamic Republic of Iran Navy (IRIN) and the Navy of the Army of the Guardians of the Islamic Revolution (IRGCN), have a long history of operating with a relatively high degree of tension in the Strait of Hormuz and throughout the Persian Gulf. Since the Revolution in 1979, there have been routine approaches by Iranian vessels on US Navy ships. These can be at the edge of visual range, all the way to in close enough proximity to hear each other’s talking voices.
While these approaches are rare with navies throughout the world, it has been a constant part of life in the Gulf. Every approach is treated as a possible threat and taken seriously, though for the most part both sides act professionally and there is rarely escalation. There have been several periods where these encounters have been taken much more seriously than others. The Tanker War was the only real time period of open hostility, with significant mining being conducted throughout the northern Persian Gulf, and the US Navy destroying several Iranian speedboats. In early 2004 there were a pair of incidents that upped tensions significantly; the detonation of a suicide boat, killing three crew members from the USS Firebolt attempting to conduct a boarding to inspect the boat, and the capture of a detachment of Royal Marines and Royal Navy Sailors conducting training of Iraqi river patrol forces. In 2007, Royal Navy and Marines were again detained by the IRGCN, this time while conducting ship inspection boardings in or near to Iraqi territorial waters. As the Joint Comprehensive Plan of Action (JCPOA) was coming into effect in January 2016, a detachment of US Navy Riverines transiting between Kuwait and Bahrain was detained after straying into Iranian territorial water around Farsi Island. These incidents were all the product of, or led to, new policies and procedures being introduced by US and coalition ships on being approached by Iranian boats.
The time period since President Trump’s inauguration has seen a number of moments of high tension. Starting with the withdrawal of the US from the JCPOA, and the labelling of the IRGC as a terrorist organisation, there has been increasing distrust between President Trump and Iranian President Hassan Rouhani. This has been coupled with escalatory actions by Iran toward the US and other coalition partners. It is widely believed that Iran perpetrated the bombing of several oil tankers near Fujairah, in the United Arab Emirates, and a month later they seized a British flagged oil tanker and her crew, holding them for two months. It is also widely believed that they have funded and armed Houthi rebels in Yemen, and assisted them in shooting down an MQ-9 Reaper. The largest crisis of this administration came after Iran shot down a US Navy operated RQ-4 Global Hawk flying in international airspace over the Strait of Hormuz. This led to the rapid planning of an – ultimately aborted – military strike into Iran. This was followed in January of this year by the US strike on Iranian General Qasem Soleimani in Iraq, which at the time seemed close to triggering retaliatory strikes from Iran on a scale that many feared would lead to open war in the Gulf. Through this period, there were many interactions between US and Iranian vessels including when the USS Boxer neutralised two Iranian drones while transiting the Strait. Despite these incidents, an escalation was averted due to a relatively underwhelming – although still casualty-inflicting – retaliatory strike on US forces in Iraq.
What led to President Trump’s tweet?
Over the last decade both sides have started recording their interactions, and rushing to publicise them as part of their respective PR campaigns. Not every interaction is released to the wider population, but at least on the US side, most are kept at an unclassified level and can released. On April 15th, a particularly well filmed and very close interaction between the IRCGN and six US Navy and Coast Guard ships was posted and picked up by the wider media. The video and accompanying photos received a much larger distribution than normal interactions, and on the morning of April 22nd, Fox and Friends – which President Trump is known to watch – aired a segment on Iran’s launch of their first satellite into space, and included some footage of the approach a week earlier. This seems to have been the primary impetus for the tweet, although a near instantaneous jump in the previously flagging oil prices following the post seems to have been a notable byproduct.
In practice, Trump’s tweet will likely create no immediate policy changes for forces operating in the region. Commanders always have the inherent right of self-defence, and that is encapsulated in the standing Rules of Engagement. The use of the word “harassment’ by the President would be an expansion of ROE, but is also one that is harder to define, so would be much less legally definable as an addendum to regional operational guidelines. Currently, there are likely several working groups assessing this, and determining what and how to implement the President’s instruction-via-Twitter. So, what is being considered?
Geography and Logistics
The US navy’s Fifth Fleet is headquartered in Bahrain, and the few ships home-ported in the region are permanently stationed there. There are some Army watercraft in Kuwait, and there are aviation assets all across the region but mostly concentrated in Qatar and Kuwait. There are no ships that maintain a constant presence in or near the Strait of Hormuz, though there are regular transits. The US Navy also has resources in other ports throughout the region, most notably in Dubai and Fujairah in the United Arab Emirates, Duqm in Oman, and in Djibouti.
There is also the issue of resupply. The US possesses the most robust ability to resupply ships at sea globally, but replenishment ships need to pick up supplies to distribute to the combatant ships at sea. Unfortunately, most of the main hubs for this are inside the gulf in Dubai and Bahrain. Fujairah has been used for this purpose for some time, but its proximity to Iran, particularly after the ship bombings last year, have made it a less desirable choice. Duqm in Oman is a relatively new port on the Northern Arabian Sea facility, and has significant issues with being geographically isolated by land. Djibouti is a port that has sufficient facilities for a lot of resupply ships, but not all, and is a full four days sail away from the entrance to the Strait or Hormuz. So, this means that there is a large issue with keeping ships outside the Gulf for long durations, and making regular transits through the Strait an uncomfortable necessity.
Iran maintains fleets both inside and outside the Persian Gulf. They are operated by both IRIN and IRGCN, although the two forces don’t traditionally play well together. IRIN is more of the conventional Navy and operate most routinely in the Persian Gulf, where the IRGCN have a reach across all of Iran but have a very strong presence in the Strait. The IRGCN have a large number of pre-positioned small boats called Fast Attack Craft (FAC) which are purpose-built military craft, and Fast Inshore Attack Craft (FIAC) which are repurposed civilian craft with ad hoc gun and missile mounts. The IRGCN routinely practice operating small boat swarms to attack larger ships with the FAC acting as Command and Control nodes for the FIAC, and have even been known to use combined small craft and air assaults, such as in the case of MV Steno Impero, the British flagged tanker seized in July 2019.
In addition to the surface threat, Iran maintains heavy missile coverage throughout the entire Strait. A variety of imported and domestically produced anti-ship cruise missiles are distributed to provide coverage though most of the trafficked sea-lanes. Additionally, they have a robust air defence system, as proven by the shooting down of the RQ-4 Global Hawk. Most of these missile systems are truck mounted systems and can be relocated on relatively short notice as a form of hardening against destruction. It is unknown as to how effectively integrated these forces are to be able to coordinate fires from shore with maritime and aerial operations. They have conducted demonstrations of this, such as their attack on a barge dressed up as a Nimitz-class Aircraft Carrier in 2015, and appeared to be getting ready to conduct a follow up attack drill this spring, though that may have been put on hold due to the killing of General Soleimani or the fact that Iran’s leadership had been significantly impacted by COVID-19.
The United States’ Fifth fleet of combatants is mostly made up of deployed ships who have sailed form their home-ports on either of America’s coasts. At any given time, there are a mix of independently deployed Destroyers, some with an anti-ballistic missile mission, a Carrier Strike Group, with a nuclear Aircraft Carrier and their complement destroyers and cruisers, and an Amphibious Ready Group made up of an Amphibious Assault Ship, and a smaller amphibious ship or two. These ships are complimented by a number of Mine Sweepers and Coastal Patrol Craft permanently stationed in Bahrain, and the Combat Logistic Force replenishment ships who circulate through the fleet.
The US also has a significant Air Force presence in Qatar, and a slightly smaller number of aircraft in Kuwait. These can work with the Air Wing coming from the Carrier, and the Marine Air Wing from the Amphibious Assault Ship. There can also be an additional Marine Air Wing in theatre as well. All of these forces can work together, and have overlapping responsibilities.
Force on Force
There has been a lot of effort made through the years trying to wargame a potential conflict between the US and Iran in the Strait. The crux is assessing the level of restraint that Iran would use. Most assessments assume that Iran will be unlikely to conduct a full-scale retaliatory strike, with ballistic missiles fired toward US sites Qatar and Bahrain. There is a strong belief that while Iran doesn’t have the best relationship with its neighbours around the Gulf, Tehran maintains the desire to avoid inciting these countries to explicitly join with the Americans against them.
The converse holds true as well. While the US has assets in nearly every gulf state except for Iran, these countries have their own self interest to worry about: overflight may not be authorised; passage through their waters, particularly those of the UAE and Oman through the Strait, may be limited or fully curtailed. Innocent passage can’t be refused, however conducting military operations without the consent of the state whose water you are sailing through is a violation of maritime law.
In an outright conflict, balancing the number of missiles able to be positioned in the Strait of Hormuz with the number of missile engagements that can be managed by US ships, puts the outcome in the Strait in the favour of Iran, at least temporarily. An engagement on a single group of ships transiting the Strait could easily overwhelm their organic defences. Any air assets that were assigned to assist a transit would also be in extreme danger from the Surface to Air missile threat. When paired with the FAC/FIAC threat, Iran holds a real advantage in being able to lock up the US’ ability to enter and exit the Persian Gulf.
Of course, after an initial strike by the Iranians, the resulting response from the US would certainly not be geographically constrained to the Strait of Hormuz. Iran has never truly displayed an ability to conduct a sustained, multi-pronged effort over a wide geographic area. In the way US naval forces are poorly configured for rapid, high intensity attacks like the FAC/FIAC threat and overwhelming missile volleys, Iran is not built to sustain large wars. In this way, Iran would most certainly win the first battle, but would also certainly lose the war.
Suggested e-learning courses related to this topic:
- Contemporary Issues in World Politics – University of Naples Federico II
- Terrorism and Counterterrorism – Georgetown University
- International Human Rights Law – Université catholique de Louvain
Suggested books for in-depth reading on this topic:
- Sea Power: The History and Geopolitics of the World’s Oceans (Admiral Jim Stavridis)
- The Twilight War: The Secret History of America’s Thirty-Year Conflict with Iran (David Crist)
- Black Wave: Saudi Arabia, Iran, and the Forty-Year Rivalry That Unraveled Culture, Religion, and Collective Memory in the Middle East (Kim Ghattas)
- Tanker War: America’s First Conflict with Iran (Lee Allen Zatarain)
Additional geopolitical reading suggestions can be found on our 2020 reading list
Purchases made using the links in this article earn referrals for Encyclopedia Geopolitica. As an independent publication, our writers are volunteers from within the professional geopolitical intelligence community, and referrals like this support future articles. Encyclopedia Geopolitica readers can also benefit from a free trial of Kindle Unlimited, which offers unlimited reading from over 1 million ebooks and thousands of audiobooks.
Anthony Clay is a former Surface Warfare Officer in the United States Navy who has served in every operational fleet, and most geographic Combatant Commands. He has an International Relations Degree from Tulane University and a Operations Research Masters Degree from the Naval Postgraduate School. Anthony finished his Naval career assigned to a staff posting within a numbered fleet, and now works in a civilian posting in the Department of Defense.
For an in-depth, bespoke briefing on this or any other geopolitical topic, consider Encylopedia Geopolitica’s intelligence consulting services.
Photo: A ridged hull inflatable boat from USS Russell participates in exercises in the Persian Gulf (US Navy Photo)