Foundations
How the system acquired its shape
Three things fixed in seventeen years and none has moved since.
Conflict coverage · Iran–Gulf
PhasesHigh confidence
The phases4 dated periods in Iran–Gulf, in order. Each opens its own section below: what happened, what the period covers, the analytical takeaway, and the key events it produced — every one of them dated and sourced individually on the timeline.
The security architecture
Why an outside power is a core actor here
Iraq's invasion of Kuwait and the campaign that reversed it left a durable American military presence hosted under bilateral arrangements with several Gulf states, and those arrangements — not any Gulf institution — are what the region's security has rested on since.
The immediate approach
The eight months that were not a war
Iran and Saudi Arabia normalised relations in Beijing in 2023, which is the last significant de-escalation the system has recorded.
The current war
Six months that reorganised the region's access
United States and Israeli strikes opened on 28 February and Israel killed Supreme Leader Ali Khamenei the same day.
FoundationsHow the system acquired its shape1971 – 1988
What happened
Three things fixed in seventeen years and none has moved since. Britain withdrew from east of Suez in 1971 and Iran occupied three islands at the strait's mouth on the eve of the UAE's federation, creating a territorial dispute that is still live. The 1979 revolution replaced one Iranian state with another and built a second army beside the first. And the Iran–Iraq war produced the Tanker War, in which attacks on commercial shipping, the reflagging of tankers and outside navies in the Gulf were all tried for the first time.
The period covers
- The Abu Musa and Tunbs dispute dates from 1971 and remains unresolved.
- The Gulf Cooperation Council was founded in 1981, in the war's second year.
- Security Council resolution 2817 of 2026 recalls resolution 552 of 1984 by name.
Key analytical point
The mechanism the current war runs on is not new. Attacking commerce to coerce a state, and pricing rather than force deciding who sails, were both demonstrated in the 1980s — which is why the Council reached back forty-two years to cite itself.
Key events in this phase
The security architectureWhy an outside power is a core actor here1990 – 2020
What happened
Iraq's invasion of Kuwait and the campaign that reversed it left a durable American military presence hosted under bilateral arrangements with several Gulf states, and those arrangements — not any Gulf institution — are what the region's security has rested on since. The nuclear file opened and closed in the same period: the 2015 agreement, the American withdrawal from it in 2018, and the 2019 Abqaiq attack that showed how much could be taken offline in a morning.
The period covers
- The Bahrain, Qatar and Kuwait basing relationships all date from this period.
- Abqaiq in 2019 removed about half of Saudi production temporarily, from a single attack.
- The Abraham Accords of 2020 changed which regional alignments were sayable in public.
Key analytical point
Gulf security was built as a set of bilateral relationships with an outside power rather than as a collective institution, and the current war is the first test of what that means when the outside power is itself a belligerent.
The immediate approachThe eight months that were not a war2023 – 2025
What happened
Iran and Saudi Arabia normalised relations in Beijing in 2023, which is the last significant de-escalation the system has recorded. Then in June 2025 Israel and the United States fought a twelve-day war with Iran that ended in an announced ceasefire — and after which the inspectors did not go back. The snapback mechanism was triggered that August and United Nations measures returned in late September. Eight months passed before the current war opened, and the interval matters: it is why June 2025 is a separate conflict rather than the first phase of this one.
The period covers
- The IAEA's last verified nuclear inventory dates from 13 June 2025, the day the strikes began.
- The E3 triggered snapback on 28 August 2025; the EU reimposed its own measures on 29 September.
- Practical modalities to resume inspections were agreed in September 2025 and no inspections followed.
Key analytical point
The twelve-day war ended and the verification did not resume. Everything the module cannot say about Iran's nuclear programme dates from this period, not from the current war.
Key events in this phase
Iran and Saudi Arabia restore relations under the Beijing agreement · Mar 2023The twelve-day war between Israel, the United States and Iran · 13 – 24 Jun 2025The E3 trigger the JCPOA snapback mechanism · 28 Aug 2025United Nations and European Union measures on Iran are reimposed · 27 – 29 Sep 2025The United States and Saudi Arabia sign a Strategic Defense Agreement · 19 Nov 2025
The current warSix months that reorganised the region's accessSince 28 February 2026
What happened
United States and Israeli strikes opened on 28 February and Israel killed Supreme Leader Ali Khamenei the same day. Iran declared the strait closed, and a week later the withdrawal of marine war-risk cover closed it commercially. Iran struck all six Gulf Arab states; the Security Council condemned the attacks in resolution 2817 and split on shipping in April. A memorandum signed in June was declared over in July and expired in August, and the heaviest exchange in more than a month followed on 1–2 September.
The period covers
- Production shut-ins peaked above eleven million barrels a day.
- Qatar lost around 17% of its liquefaction capacity for a period estimated at up to five years.
- Two Gulf states have signed defence arrangements outside the Gulf Cooperation Council since the war began.
Key analytical point
The strait was never sealed and never physically closed. What closed it was the price of insuring a voyage through it — which is the module's central finding and the subject of its flagship analytical note.
Key events in this phase
United States and Israeli strikes on Iran open the war · 28 Feb 2026Supreme Leader Ali Khamenei is killed · 28 Feb 2026Iran declares the Strait of Hormuz closed to normal commercial traffic · 28 Feb 2026Marine war-risk cover for the Gulf is terminated and repriced · 5 Mar 2026Security Council Resolution 2817 condemns Iranian attacks on Gulf states · 11 Mar 2026The United States and Iran sign a memorandum of understanding · 17 Jun 2026The memorandum of understanding expires unextended · 17 Aug 2026United States and Iranian exchange of strikes · 1 – 2 Sep 2026
Evidence and grading
- Phase
- An editorial period, not a schema state. A phase is Vigil’s own division of the background into dated stretches; the events inside it are dated and sourced individually on the timeline.
- Confidence
- How well established Vigil considers this assessment to be. It is not a measure of how severe the situation is.