Punitive deterrence against economic assets in the US–Iran naval confrontation, 1–26 September 2026
ABSTRACT
On 1 September 2026 US forces first applied a “tanker for tanker” policy, answering Iranian attacks on shipping in the Strait of Hormuz by striking Iranian state-owned tankers. The article asks whether this shift from military targets to economic assets limited escalation, reconstructing the 1–26 September strike sequence and Kpler transit data through Jervis’s security dilemma and Lupovici’s fourth wave of deterrence theory. Iran answered with about 25 ballistic missiles the same day and struck at US warships on 4 September; daily transits stayed in single or low double digits. Economic punishment relocated escalation instead of containing it and reduced bargaining to a trade between the US blockade and Hormuz transit.
1. The puzzle: punishment aimed at revenue
On 1 September 2026 US forces struck two Iranian state tankers in their engine rooms, the first application of the “tanker for tanker” policy approved by President Donald Trump (Ravid, 2026). It came after the war that began on 28 February 2026 had turned into a tanker war of reciprocal ship attacks from July (Al Jazeera, 2026b). The research question is whether moving deterrence to economic assets limited US–Iranian escalation. Between 1 and 26 September it did not: economic punishment widened the set of targets and reduced bargaining to a trade between the US naval blockade and transit through Hormuz. The scope is the strait and the Gulf of Oman, excluding the Houthi–Saudi front and the pipeline attack launched from Iraqi territory. Statements by the Islamic Revolutionary Guard Corps (IRGC) and Iranian state media are treated as unverified claims.
2. Denial, punishment and the fourth wave
Deterrence by denial seeks to prevent an adversary’s action from succeeding; deterrence by punishment threatens an unbearable cost after the action. The 1 September operation combined the two. According to Axios, the roughly 100 targets struck that day included IRGC air defences, radars, mine-laying capacity and anti-ship cruise missile launchers (Ravid, 2026), all of which reduce Iran’s ability to attack ships. Striking two state tankers left that capacity untouched and hit a revenue-bearing asset; “tanker for tanker” here denotes this punitive component alone.
Lupovici (2010) labels the work that adapts classical inter-state nuclear deterrence to asymmetric threats the fourth wave of deterrence theory. The tanker policy adds a specific variable: the object of the threat is the adversary’s economic asset, not its military capability. Such a threat works only while the asset still carries high value for the adversary.
Jervis (1978) argues that the security dilemma is most severe where offence holds the advantage and offensive and defensive postures cannot be told apart. The Hormuz tanker war meets each condition. From the start of the conflict to 8 August, 15 vessels of ADNOC, the UAE national oil company, were hit by missiles and drones, with one crew member killed and 20 people injured (Al Jazeera, 2026a). Indistinguishability shows in language: Axios reported the US strikes as retaliation for attacks in Hormuz (Ravid, 2026), while the IRGC said the tankers it hit had used unauthorised routes (Barabas et al., 2026). Where each side frames its strike as a response, Jervis’s framework predicts that mutual restraint will be hard to establish.
3. The September sequence
| Date | US action | Iranian action | Source |
|---|---|---|---|
| 1 Sept | Two state tankers and about 100 military targets | About 25 ballistic missiles (10 intercepted, 3 fell without casualties); about two dozen drones at US bases in Bahrain | Ravid (2026) |
| 4 Sept | — | Ballistic missiles from Isfahan and Kerman at US warships | Barabas et al. (2026) |
| 5 Sept | M/T Downy (off Kharg), M/T Stark 1 (near Jask), M/T Kylo/Noxen (Gulf of Oman) | Claimed strikes on three tankers and three US-linked vessels | Brennan et al. (2026) |
| 6 Sept | — | Qalibaf declares the period of proportional response over | Brennan et al. (2026) |
Punishment did not prevent retaliation. Iranian sources reported at least 4 dead and at least 35 injured in Kuhestak, and Iran responded the same day with missiles and drones (Ravid, 2026). On 4 September the IRGC targeted US warships (Barabas et al., 2026): within three days Iran had moved from tankers to US military platforms.
In the second round, ABC News reported that two of the vessels struck on 5 September were permanently disabled and one destroyed outright. CENTCOM commander Admiral Brad Cooper stated the policy’s ratio: fire on two US ships and the United States would impose an even higher economic cost. The next day Iran’s chief negotiator, Mohammad Bagher Qalibaf, announced that the period of proportional response had ended and that responses would be faster, heavier and more painful (Brennan et al., 2026). By 6 September no shared measure remained to regulate escalation.
4. Why punishment did not restrain
A devalued target
According to Reuters, the naval blockade CENTCOM resumed in mid-July had halted Iran’s crude exports (Liu, 2026; Liu & Chow, 2026). Ninety per cent of those exports had moved through Kharg Island (Al Jazeera, 2026b), and one tanker struck on 5 September lay off Kharg. The policy therefore targeted assets the blockade had already largely stripped of their revenue function. Destroying a tanker of a state whose exports have stopped adds less cost than cutting a working export chain; this inference derives from the timing, not from the sources. Exposure on the other side was high: ADNOC’s 15 damaged vessels show that Gulf states’ maritime assets are usable targets for Iran. The symmetrical formula thus leaves Iran’s adversaries more exposed than Iran.
Cost returning to the punisher
Brent futures settled at $96.28 per barrel on Friday 4 September, against a pre-war level of about $70, and the US average diesel price reached a record $5.85 per gallon. In a Reuters/Ipsos poll at the end of August, 31% of Americans supported the war and 63% opposed it, and Trump’s approval rating had fallen from 40% to 33% since the war began (Al Jazeera, 2026b). Part of the cost of each round reaches the punishing state’s own consumers, and as domestic support weakens the threat to sustain punishment loses credibility in Tehran.
Transit as the coercive objective
Kpler counted 4 ships through the strait on Thursday 3 September and 9 the day before, against a 10-day average of about 15 and a pre-war average of about 125 large commercial vessels a day on the same metric (Liu, 2026). On 9 September transits fell to 7, from 11 the previous day (Liu & Chow, 2026); on 24 September they were 9, half the 10-day average (Reuters, 2026). The series shows no lasting rise after the policy began. Kpler omits vessels with transponders switched off (Liu & Chow, 2026), but the gap applies equally before and after 1 September and does not reverse the trend.
5. Alternative explanations considered
One reading holds that economic punishment pushed Iran towards negotiation. According to Iranian state media, Foreign Minister Abbas Araghchi passed three conditions to US Special Envoy Steve Witkoff on the margins of the UN General Assembly on 22–23 September: lifting of the naval blockade, release of frozen assets, and an end to the war on all “resistance” fronts (The Standard, 2026). A seven-day plan presented on 24–26 September provided for a halt to regional conflicts including Lebanon and Yemen, release of about $12 billion in frozen assets, lifting of oil sanctions and an end to the blockade, leaving the reopening of Hormuz to the seventh day; the talks produced no immediate result (AFP, 2026). These documents do not show that punishment worked: Iran priced the strait as the return for economic concessions and placed reopening last. The tanker strikes left Iran’s choice to restrict the strait unchanged and converted the strait’s bargaining value into an explicit list of trades.
A second reading, that the 1 September salvo was a calibrated reply leaving room for de-escalation, is weakened by the strike on US warships three days later.
6. What the case shows about deterrence theory
The case refines the fourth-wave agenda on one point: punishment against economic assets competes with denial of the same revenue. The more effectively the blockade cut Iran’s exports, the less a threat against Iranian tankers was worth, so the first instrument emptied the second. This is the article’s inference, not a claim made by Lupovici (2010). The case fits Jervis’s (1978) prediction: offence advantage at sea and mutually framed retaliation removed a common threshold, and the ratios announced by Cooper and Qalibaf replaced restraint with escalation rules.
7. Outlook: Türkiye, Saudi Arabia and the World
The first October benchmark is the IEA Oil Market Report scheduled for 14 October (International Energy Agency, 2026). If a phased exchange of blockade for strait access is accepted on the basis of the seven-day plan, the tanker-for-tanker policy loses its object. If no exchange occurs, Qalibaf’s abandonment of proportionality points to more frequent Iranian targeting of US platforms and Gulf vessels. If the conflict extends into 2027, retaliation against economic assets could become attrition testing each side’s cost tolerance.
For Türkiye the channel is the energy bill. Ember’s June 2026 analysis estimated that the Hormuz crisis could add about $14 billion to Türkiye’s 2026 costs (Gümüş, 2026); the tanker war extends the conditions behind that estimate into the fourth quarter. The indicator for Ankara is whether October contacts attach dates to blockade and strait steps.
For Saudi Arabia, the Yemen front is part of Araghchi’s conditions and the seven-day plan (AFP, 2026; The Standard, 2026); without an exchange, Riyadh faces restricted Hormuz transit and the Yemen conflict at once.
8. Conclusion
Moving deterrence from Iran’s military capacity to revenue-bearing state assets did not limit escalation in September 2026: Iran fired missiles, targeted US warships and abandoned proportionality, while daily Kpler transits stayed between 4 and 11. The blockade had already stripped tankers of marginal value, exposure at sea was greater among Iran’s adversaries, and record diesel prices and falling public support returned part of the cost to the punisher. The concrete result was a bargain in economic units, with the strait offered against the blockade, frozen assets and sanctions. The findings rest on open sources; Iranian decision-making and US targeting assessments could not be examined.
SOURCES
AFP. (2026, 26 September). Iran offers seven-day plan to reopen Strait of Hormuz. The Vibes. https://www.thevibes.com/articles/world/127695/iran-offers-seven-day-plan-to-reopen-strait-of-hormuz
Al Jazeera. (2026a, 8 August). UAE says Iran targeted ADNOC tanker in Hormuz, no casualties. https://www.aljazeera.com/news/2026/8/8/uae-says-iran-targeted-adnoc-tanker-in-hormuz-no-casualties-2
Al Jazeera. (2026b, 6 September). US, Iran engaged in tanker war: Where is the months-long conflict headed? https://www.aljazeera.com/news/2026/9/6/us-iran-engaged-in-tanker-war-where-is-the-months-long-conflict-headed
Barabas, P., Scarpellini, M., & Euronews Persian. (2026, 5 September). Iran says it attacked US-linked vessels and tankers as Hormuz clashes intensify. Euronews. https://www.euronews.com/2026/09/05/iranian-media-report-us-strike-on-iranian-oil-tanker-near-kharg-island
Brennan, D., El-Bawab, N., & Pereira, I. (2026, 6 September). US strikes oil tankers, Tehran claims attacks on US-linked vessels. ABC News. https://abcnews.com/International/live-updates/iran-live-updates-centcom-targeted-iranian-forces-posed/?id=136080582
Gümüş, B. S. (2026, 12 June). Hürmüz krizi Türkiye’ye 14 milyar dolara mal olacak [The Hormuz crisis will cost Türkiye $14 billion]. Ember. https://ember-energy.org/app/uploads/2026/06/TR_Hurmuz-krizi-Turkiyeye-14-milyar-dolara-mal-olacak-1.pdf
International Energy Agency. (2026). Oil market report – October 2026. https://www.iea.org/events/oil-market-report-october-2026
Jervis, R. (1978). Cooperation under the security dilemma. World Politics, 30(2), 167–214. https://doi.org/10.2307/2009958
Liu, S. (2026, 4 September). Gulf shipping traffic via Hormuz keeps below 10-day average, data shows. gCaptain. https://gcaptain.com/gulf-shipping-traffic-via-hormuz-keeps-below-10-day-average-data-shows/
Liu, S., & Chow, E. (2026, 10 September). Hormuz shipping traffic falls to single digits, data shows. gCaptain. https://gcaptain.com/hormuz-shipping-traffic-falls-to-single-digits-data-shows/
Lupovici, A. (2010). The emerging fourth wave of deterrence theory—Toward a new research agenda. International Studies Quarterly, 54(3), 705–732. https://doi.org/10.1111/j.1468-2478.2010.00606.x
Ravid, B. (2026, 1 September). U.S. strikes Iran tankers under new “tanker for tanker” policy. Axios. https://www.axios.com/2026/09/02/iran-tankers-hormuz-attacks-oil
Reuters. (2026, 25 September). Allies unite behind Saudi Arabia as Houthis step up attacks. The Kathmandu Post. https://kathmandupost.com/world/2026/09/25/allies-unite-behind-saudi-arabia-as-houthis-step-up-attacks
The Standard. (2026, 23 September). Iran submits conditions for reopening of Hormuz to US representative, state media says. https://www.thestandard.com.hk/world/article/343544/Iran-submits-conditions-for-reopening-of-Hormuz-to-US-representative-state-media-says
Furkan Mahmut Tameroglu