So with the current impasse locked in place, which way are the winds blowing in the Persian Gulf?

The answer doesn’t lie with the two opposing governments, but with Iran’s own specialist military forces, the Revolutionary Guards, who are already pursuing their own campaign.Since last year, the challenge for the Iranian government has been how to regain the initiative from the Trump administration’s strategy of “maximum pressure”, designed to subject the Islamic republic’s economy to intolerable pain.

President Rouhani and his foreign minister, Javad Zarif, are trying to forge and protect vital economic links with other countries, especially in Europe, but their efforts have so far been fruitless. Meanwhile, the supreme leader has ruled out any direct diplomatic engagement with the Americans, and has rebuffed European calls for negotiations over his country’s nuclear programme or its activities in the Middle East, such as its support of Syria’s Bashar al-Assad.

That leaves open the possibility of a quasi-military counter-offensive by the guards, targeting both the Americans and the “weak” Rouhani government itself. Inside Iran, the guards have stepped up their seizures of dual and foreign nationals, including from the US, UK and Australia, while using domestic media outlets to jab at Rouhani and Zarif. They have not only downed an American drone but also apparently attacked tankers in UAE ports and the Persian Gulf.

On 19 July, the guards seized the UK-flagged tanker Stena Impero, acting on the supreme leader’s command for retaliation after the Iranian supertanker Adrian Darya 1 was impounded in Gibraltar. (The Adrian Darya was released last month after Iran guaranteed it the ship would not deliver oil to the Assad regime. That guarantee was shortly broken, while Stena Impero is still held in the southern Iranian port of Bandar Abbas.)

Officially, Saturday’s attacks were the work of the Houthi insurgents who control much of Yemen, and who have claimed responsibility. Unofficially, the Revolutionary Guards have trained and supplied the Houthis through their series of strikes against Saudi targets this year. And now the US is claiming that the latest attacks, as well as some of the earlier ones, came from not from Yemen but from Iranian-backed forces in Iraq.

Of course, both the Iranian regime and those reflexively suspicious of any US government will note that there is still no conclusive proof of Tehran’s complicity in this latest incident. They will question anyone who accuses Iran of perpetrating the tanker attacks in the Strait of Hormuz, putting pressure on the route for a fifth of the world’s oil supply.

But in a shrewd response to US pressure and Iranian counter-pressure, the Revolutionary Guards are openly taking the lead in Tehran’s response to the Trump strategy, as the Islamic republic tries to avert catastrophic economic crisis. As General Ali Hajizadeh, the guards’ air force commander, made clear on Sunday: “In addition to US bases in the region, we have all their vessels, including aircraft carriers and warships, under fire of our missiles to a radius of 2,000km, and are constantly monitoring them.”

At the very least, the guards have sunk Trump’s ambition for an on-camera handshake with an Iranian VIP, which he might have pursued later this month at the UN general assembly. The far more important issue now is what other casualties should be expected, from further death and destruction in the Middle East to the choking of the world’s oil supply.

To go by Trump’s tweets, more fire and fury is on the way. But the Revolutionary Guards are already on the march, and there is little no precedent for Trump acting on his words. To paraphrase Joseph Stalin’s quote about the Pope: “How many divisions does a Twitter account have?”