Bessent's Oman ultimatum: US draws a red line on Hormuz tolling

Washington has issued a direct warning to Muscat over any role in facilitating Iran's reported attempts to install a tolling system on the Strait of Hormuz — the world's most critical oil chokepoint. The question now is whether Bessent's threat is a negotiating posture or a genuine readiness to impose costs.

By Monexus Staff Writermiddle-east5-minute read28 May 2026☆ Save ↗ Share ⎙ Print

On 28 May 2026, Scott Bessent delivered an unambiguous warning from the Treasury Department. The United States would deal firmly with any nation that assisted Iran in imposing tolls on the Strait of Hormuz, the narrow waterway through which roughly a fifth of the world's oil passes daily. Bessent named Oman explicitly — a significant diplomatic escalation that placed Muscat at the centre of a confrontation it has spent decades trying to avoid.

The threat marks the sharpest articulation yet of Washington's position on what the Trump administration describes as an Iranian scheme to monetise control of one of the world's most strategically sensitive maritime corridors. For a small Gulf sultanate whose foreign policy has historically been defined by equidistance and careful hedging between regional powers, the directness of Bessent's language represents a moment of acute pressure.

The immediate provocation

The thread connecting Bessent's statement to Iranian behaviour runs through Tehran's long-standing interest in Hormuz as a geopolitical lever. Iran has repeatedly threatened to close or restrict the strait during periods of heightened tension with the West, most recently during the 2018-2019 maximum pressure campaign and again following the collapse of the original nuclear deal. What is new — and what appears to have prompted the Treasury Secretary's intervention — is the notion of a tolling mechanism rather than outright blockade: a system in which transit fees, rather than physical obstruction, would become the instrument of Iranian leverage.

Whether such a system exists in operational form or is still in the planning stage remains unclear from the sources reviewed. What is clear is that the administration views any movement in this direction as a direct challenge to US interests and has chosen to pre-empt it with a public warning aimed at Oman's government.

The targeting of Oman specifically reflects Muscat's unique geographical position. The Sultanate controls the Musandam peninsula, a finger of territory jutting into the Strait of Hormuz that gives Oman sovereignty over the western bank of the waterway. Oman also maintains diplomatic channels with Tehran that most Gulf states do not — a legacy of Sultan Qaboos's patient shuttle diplomacy, and one that his successor, Sultan Haitham bin Tariq, has largely continued. These channels make Oman both a potential enabler of any Iranian scheme and a potential pressure point.

Oman's precarious position

Muscat has historically navigated the region by staying close enough to Washington to guarantee security — Oman hosts US military facilities and signed a US-Oman Free Trade Agreement in 2009 — while avoiding the direct confrontation with Iran that its neighbours have pursued. The Suleiman al-Mahrooqi / Sultan Qaboos doctrine of constructive neutrality has served the Sultanate well, allowing it to avoid the Saudi-Iranian rivalry that has destabilised other Gulf states.

Bessent's threat now tests that positioning directly. If Iran is indeed moving toward a tolling system, Oman's role could be indispensable: Muscat controls access infrastructure, port facilities, and the diplomatic proximity that would make such an arrangement viable. The United States is effectively telling Oman that the costs of facilitating that arrangement would outweigh the benefits of continued ambiguity.

What Muscat does next is not yet clear from the available sources. The Omani government had not issued a formal response as of publication. But the pressure is structural: the United States provides the security umbrella that underwrites Oman's regional stability, and the Treasury Department is making explicit that maintaining that umbrella is contingent on Muscat's posture toward Iran's Hormuz ambitions.

The Iran calculus

The broader context is the renewed confrontation between Washington and Tehran over the nuclear file. Negotiations over a new agreement collapsed in early 2026, and the administration has reverted to maximum pressure, reimposing and expanding sanctions. Iran's response has been to signal increased nuclear activity and, according to the sources reviewed, to explore economic countermeasures outside the conventional toolbox of missile launches and proxy attacks.

A tolling system on Hormuz would be qualitatively different from previous Iranian threats. A blockade invites immediate US military response; a toll is an economic mechanism that could be framed, at least initially, as an exercise of regulatory authority over a strategically vital corridor. Iran might calculate that the ambiguity between blockade and toll gives it room to extract concessions without triggering the kinetic response an outright closure would provoke.

That calculation, if it exists, now faces a significant complication. Bessent's statement — and the specificity of the Omani targeting — suggests the administration is not willing to let that ambiguity develop. The question is whether the threat of secondary sanctions or other punitive measures against Muscat is sufficient to deter Omani cooperation, or whether Washington has signalled a willingness to escalate further.

What comes next

The stakes are immediate and structural. In the short term, the US warning creates pressure on Oman to demonstrate to Washington that it is not facilitating Iranian tolling ambitions — which may require Muscat to take visible steps, such as restricting port access or sharing intelligence on Iranian activities near the strait. If Oman is seen to demur, the Treasury Department's threat moves from rhetorical to substantive: financial sanctions on Omani entities, exclusion from the US financial system, or the withdrawal of trade privileges under the FTA.

In the medium term, the episode underscores a structural reality that has been reshaping Gulf politics since the 2019 Saudi Aramco attacks and the subsequent US retrenchment from the region: the United States still treats Hormuz as a core interest, but its willingness to defend that interest militarily is no longer taken for granted by regional partners. That ambiguity has forced Washington to rely more heavily on financial tools — sanctions, threats, pressure — as instruments of deterrence. Bessent's statement is the latest example of that approach.

For Iran, the calculation is more complex. Tehran may interpret the ultimatum as a sign of weakness — a Treasury Secretary wielding threats rather than a carrier strike group — or it may interpret it as a signal that the United States is prepared to act more aggressively than previously assumed. The sources reviewed do not include any Iranian response to Bessent's statement as of the time of writing.

What is certain is that the Strait of Hormuz has returned to the centre of US-Gulf-Iranian relations, and that Oman's position — historically comfortable, historically ambiguous — is no longer sustainable in its previous form. Muscat will be required to show its hand, and the United States has made clear what the price of the wrong choice will be.

Wire provenance

This editorial synthesis draws on the following public wire/social posts:

https://t.me/Megatron_Ron
https://t.me/Middle_East_Spectator
https://t.me/FarsNewsInt
https://t.me/JahanTasnim
https://t.me/GeoPWatch