MIL Weekly — Iran–U.S. War — September 11, 2026
The biggest change in this week’s MK5-MIL assessment is that Saudi Arabia’s main workaround for the Strait of Hormuz is now under pressure too. Iran-backed Houthi forces captured the port of Mocha and the strategic island of Mayun at the Bab el-Mandeb, while Saudi Arabia temporarily shut its East-West oil pipeline after a drone attack.
Hormuz remains badly degraded, which had made the Red Sea route increasingly important for Saudi oil exports. Pressure on both routes leaves the regional energy network with fewer practical substitutes if either chokepoint deteriorates further.
The conventional military balance still favors the United States, but Washington hasn’t turned that advantage into a political settlement. Iran still has enough missiles, maritime capability, allied armed groups, and ability to disrupt energy flows to keep the cost of continued pressure high.
What changed this week
Four indicators stand out.
Saudi export workaround: ↑ Under rising pressure
The Houthis captured Mocha on September 10 and Mayun, also known as Perim, on September 11. Mayun sits inside the Bab el-Mandeb, the southern entrance to the Red Sea, and its capture gives the group a more consequential position near one of the world’s most important shipping lanes.
Saudi Arabia had increasingly relied on its East-West pipeline to move crude from the Persian Gulf side of the country to Yanbu on the Red Sea, bypassing Hormuz. By early June, exports through that route had exceeded 5 million barrels per day.
Saudi Arabia temporarily shut the pipeline after a drone attack on September 10. The shutdown didn’t eliminate Saudi exports, but it weakened one of the most important alternatives to Hormuz and increased the importance of longer or more constrained routes through the Red Sea, Suez Canal, and Egypt.
Hormuz disruption: ↑ Rising again
Iran said on September 9 that it attacked 10 vessels near the Strait of Hormuz after U.S. forces sank five Iranian oil tankers. Iran also launched ballistic missiles toward a U.S. base in Jordan.
Visible commercial traffic through Hormuz subsequently fell to seven vessel transits on September 10, compared with roughly 125 large commercial vessels per day before the war. Ships operating without normal tracking signals mean the true number is higher, but commercial traffic remains far from normal.
Energy-system stress: ↑ Rising
The International Energy Agency now expects global oil supply to fall by 5.7 million barrels per day in 2026, or about 6%. Saudi crude supply fell to 6 million barrels per day in August, its lowest level in more than three decades, while global inventories declined at a rate of 3.1 million barrels per day.
That leaves the market with less room to absorb another major disruption. Earlier in the war, inventories, alternative routes, spare capacity, and demand reductions helped soften the shock. Those buffers are becoming less effective as the conflict drags on.
Negotiation pressure: ↑ Rising
Higher energy costs are giving both sides more reason to explore a limited maritime agreement even though the broader political dispute remains unresolved. A narrow arrangement over commercial shipping would be easier to reach than a comprehensive settlement covering sanctions, nuclear policy, missiles, and regional security.
That doesn’t mean a maritime deal is close. It means the incentives to contain one of the war’s most expensive pressure points are stronger than they were a few weeks ago.
Regional energy network
This week’s strongest strategic development is the growing interaction between Hormuz and Bab el-Mandeb.
When Hormuz became unreliable, Saudi Arabia increased use of the East-West pipeline to move crude to the Red Sea. Tankers leaving Yanbu could then travel south through Bab el-Mandeb toward Asian customers, reducing Saudi dependence on the Persian Gulf chokepoint.
The Houthi advance now reduces the value of that workaround. Red Sea shipping had already fallen sharply because of earlier Houthi attacks, and the seizure of territory around Bab el-Mandeb puts more pressure on a route that had become more important during the Iran war.
Saudi Arabia still has options, but none is a perfect substitute. Oil can travel north through the Red Sea toward the Suez Canal or Egypt’s pipeline system, while other Gulf producers have their own routes around Hormuz. Those alternatives are longer, more expensive, or more limited in capacity.
MK5-SC therefore sees a regional energy network losing redundancy rather than two isolated chokepoints failing independently.
Trend: ↑ Network pressure rising
Confidence: High
Strait of Hormuz
Hormuz remains the conflict’s main maritime pressure point.
Commercial vessel tracking showed only seven visible commodity-ship crossings on September 10. The recent 10-day average was 15, compared with about 125 large commercial vessels per day before the war.
The true flow is larger because some tankers are crossing with Automatic Identification System tracking disabled. A tanker that disappears from commercial tracking hasn’t necessarily stopped moving oil, so visible traffic can make the physical disruption look worse than it is.
The opposite problem matters too. Dark crossings, military escorts, delayed departures, altered routes, higher insurance costs, and reduced traffic all show that the shipping system is operating under severe stress even when oil continues to move.
MK5-SC therefore continues to classify Hormuz as a degraded network constraint rather than a completely closed strait.
Trend: ↑ Disruption rising
Confidence: High that normal commercial shipping remains severely impaired; medium on precise physical throughput
Energy pressure
The global oil system has less room to absorb additional disruption than it did earlier in the war.
The IEA expects world oil supply to decline by 5.7 million barrels per day this year. Saudi output fell by 2.3 million barrels per day in August to 6 million, while global stocks were drawn down at a record rate.
Demand is also falling because of high prices, but supply is falling faster. That imbalance keeps pressure on crude and refined fuels even when markets briefly respond to diplomatic optimism.
Brent crude briefly approached $110 this week before retreating on September 11. Even after the decline, it remained above $100 and more than 8% higher for the week.
U.S. refining capacity adds another constraint. Refineries are already operating near their practical limits, which reduces the country’s ability to offset a global supply shock simply by producing more domestic crude.
The economic effects are becoming more visible outside energy markets. The University of Michigan’s preliminary September consumer-sentiment index fell to 47.8 from 51.7 in August, while one-year inflation expectations rose from 4.0% to 4.6%. Higher gasoline prices were among the pressures consumers cited.
MIL doesn’t assume that fuel prices automatically determine U.S. military policy. They do, however, increase the domestic economic cost of maintaining the current strategy.
Trend: ↑ Strategic importance rising
Confidence: High that the economic effect is material; medium on how strongly it changes U.S. decision-making
Diplomacy
The case for renewed negotiations is stronger than the case for an imminent peace agreement.
The maritime problem offers a narrower bargaining space than the larger conflict. Both governments could benefit from reducing attacks on commercial shipping without resolving every dispute between them, which makes a limited Hormuz or maritime arrangement more plausible than a comprehensive settlement.
Frozen MK5-MIL model estimates
These are model judgments rather than empirically calibrated probabilities. This report freezes them as the September 11 baseline for future CL scoring.
- Substantive U.S.-Iran negotiations within 1–2 months: 65–75%
- Limited Hormuz or maritime agreement: 35–45%
- Broad ceasefire covering most direct fighting: 20–30%
- Durable political settlement: under 15%
The model expects diplomatic activity because the economic costs of the conflict are increasing for Iran, the United States, Gulf exporters, energy importers, and commercial shipping. It remains skeptical of a comprehensive settlement because sanctions, nuclear policy, missile capabilities, regional influence, and security guarantees are much harder to resolve than navigation through one strait.
Military balance
The conventional balance hasn’t materially changed.
The United States can strike Iranian military infrastructure, destroy ships, maintain substantial regional forces, and escort commercial traffic at a scale Iran can’t match conventionally. Iran doesn’t need conventional parity to impose costs, though.
Tehran needs enough surviving capability to make U.S. pressure expensive through missiles, drones, maritime attacks, allied armed groups, and disruption of regional energy flows. The September 9 exchange shows that Iran still has meaningful retaliatory capacity despite months of military and economic pressure.
MIL therefore continues to classify the war as an asymmetric coercive contest rather than a conventional contest Iran could plausibly win outright.
The main escalation indicator is whether retaliation remains calibrated. If U.S. strikes produce bounded Iranian responses and Iranian attacks produce limited U.S. retaliation, the conflict can remain violent but contained. If each response begins producing a larger counter-response, escalation can become driven increasingly by feedback rather than deliberate control.
Trend: ↑ Escalation pressure rising
Confidence: High
Iranian economic pressure
Washington’s economic strategy is producing substantial effects.
Sanctions and the maritime blockade have reduced Iranian oil revenue, restricted access to foreign currency, lowered imports, and increased domestic economic pressure.
The unresolved question is whether economic deterioration translates into political concessions. Economic pain and political capitulation aren’t the same thing, and Iran still has ways to soften some of the pressure.
Reuters reported on September 10 that Iranian oil revenue can be converted into credits for Chinese goods through a barter-like mechanism outside conventional Western-controlled banking channels. The reporting supports the existence and structure of the mechanism, though some specific alleged transactions remain unverified.
MIL therefore doesn’t treat worsening Iranian economic conditions as evidence that capitulation is imminent.
Trend: ↑ Pressure rising
Confidence: High on economic deterioration; low-to-medium on its political effect
DCT transition check
DCT sees more structural stress than it did during the quieter phase of the war.
The United States has weakened Iran’s maritime capabilities, but normal shipping through Hormuz hasn’t returned. Economic coercion is hurting Iran, while Iranian retaliation is again raising global energy costs. Saudi Arabia used the Red Sea to reduce dependence on Hormuz, but Houthi advances are now putting more pressure on that workaround.
Those relationships suggest the previous coercive equilibrium is becoming less stable.
There is still evidence of restraint. Saudi Arabia didn’t immediately launch a major military response after the pipeline attack, and outside governments continue pressing for maritime negotiations.
DCT therefore classifies the system as transition-prone rather than already operating under a fundamentally new regime.
Discordance: ↑ Rising
Coherence: ↓ Falling
Transition pressure: ↑ Rising
Confidence: Medium-high
CL calibration check
This is the first Iran-U.S. report frozen in this formal weekly format, so CL shouldn’t retroactively manufacture precise forecasts from earlier qualitative analysis.
This report establishes the baseline for future scoring.
Frozen forecasts
- Substantive negotiations within 1–2 months: 65–75%
- Limited Hormuz or maritime agreement: 35–45%
- Broad ceasefire: 20–30%
- Durable political settlement: under 15%
- Continued severe maritime disruption: favored
- Continued Iranian economic deterioration: favored
- Continued regional proxy pressure: favored
- Fundamental expansion into a substantially larger conventional war: not the baseline
Future reports can now resolve or update these estimates against an explicit prior record.
CL should also track whether MIL identifies the mechanisms driving change rather than only whether an event happens. The principal mechanisms frozen for this cycle are maritime coercion, Iranian economic endurance, U.S. economic feedback, regional proxy activity, and the availability of a narrow maritime off-ramp.
Source check
Evidence quality is relatively strong for the central claims in this week’s report.
High-confidence evidence includes IEA oil-supply estimates, commercial vessel-tracking data, market prices, official Saudi statements, and the University of Michigan consumer survey.
Medium-to-high-confidence evidence includes Reuters and Associated Press reporting based on multiple government, regional, shipping, and industry sources.
Medium-confidence evidence includes estimates of actual Gulf oil movement because ships increasingly disable tracking systems. Different analytics firms can therefore produce materially different estimates of physical throughput.
Lower-confidence evidence includes individual U.S., Iranian, Houthi, or militia claims about successful strikes, damage, interceptions, or casualties when independent confirmation is unavailable.
MIL should therefore distinguish confirmed attack activity from claimed tactical success.
Trend board
- U.S. conventional military advantage: → Stable
- Iranian conventional capability: → Degraded but persistent
- Iranian maritime disruption: ↑
- Hormuz shipping conditions: ↓
- Saudi alternative-route resilience: ↓
- Iranian economic pressure: ↑
- U.S. economic exposure to the war: ↑
- Negotiation activity: ↑
- Limited maritime-deal probability: ↑
- Broad peace probability: → Low
- Houthi regional pressure: ↑ Strongly
- Bab el-Mandeb risk: ↑ Strongly
- Global energy-system stress: ↑
- Major uncontrolled escalation risk: ↑
- Immediate large U.S. ground-war risk: → Low
MIL outlook
The most likely near-term path remains continued conflict accompanied by more serious attempts to negotiate around specific parts of the war.
The United States still has enough military power to keep degrading Iranian capabilities and restricting Iranian oil exports. Iran still has enough asymmetric capacity to keep that strategy costly, and the Houthi advance makes the regional energy problem harder because it reduces the usefulness of routing exports around Hormuz.
Iran’s own economic position is also getting worse. Washington is trying to make continued Iranian resistance more expensive than compromise, while Tehran is trying to make continued U.S. pressure more expensive than compromise.
Neither side has yet shown that it can force the other across that threshold.
A limited maritime arrangement therefore remains more plausible than a comprehensive settlement because it addresses one of the highest-cost parts of the conflict without requiring either government to settle every underlying dispute. The danger is that both sides may instead conclude that another round of escalation would improve their bargaining position.
Bottom line
MIL sees no decisive military conclusion this week. The most important change is in the regional energy network, where Saudi Arabia’s principal route around Hormuz is now under greater pressure just as Hormuz itself remains severely degraded.
Washington’s economic strategy continues to impose serious costs on Iran, but Iran and allied groups still have enough asymmetric capability to push part of those costs back into the global economy. DCT therefore sees the current coercive equilibrium becoming less stable, while SC sees fewer substitutes available if another major route or piece of infrastructure fails.
MIL continues to favor prolonged coercive bargaining over either decisive military victory or near-term comprehensive peace. The main thing to watch now is whether the pressure produces a narrow maritime agreement before another retaliation cycle pushes the conflict into a more difficult regional phase.