The attack on Saudi oil facilities is the latest, most violent, example of an escalating series of gambits by rival powers in the Gulf aimed at achieving their objectives by all measures short of all-out war.

But the chances of avoiding such a devastating conflict diminish each time the stakes are raised.

Iran has denied responsibility for the attack on an oil field and refining facility, while the US, Saudi Arabia and their allies have hesitated over the geographical origin of the airstrikes. The size and sophistication of the operation however points to a state actor, and it fits a pattern in recent months of increasingly bold Iranian moves intended to raise the costs of the US campaign of maximum pressure and the Saudi war in Yemen.

Until now, Iranian harassment of oil tankers travelling through the strait of Hormuz and the downing of a US surveillance drone have appeared calibrated to stop short of triggering a military response. If Iran is indeed behind Saturday’s strikes, it marks a significant step towards more reckless action by Tehran, possibly emboldened by the departure of Donald Trump’s national security adviser, John Bolton, and the desperation of Iran’s economic plight.

“What is clear is that the strategy of bombing Yemenis and starving Iranians into submission is more likely to backfire than bring the desired results,” said Ali Vaez, an Iran expert at the International Crisis Group. “Iran has less to lose and is less risk-averse.”

Trump’s tweet about being “locked and loaded” echoed his claim the US was “cocked and loaded” in response to the downing of a US drone in June. But having agreed to launch retaliatory missile strikes then, Trump changed his mind, saying the risk of casualties made it a disproportionate response.

Now without Bolton at his side making the case for war, Trump appears even more cautious, trapped between not wanting to appear weak and anxious to avoid going to war in the midst of a re-election campaign. His solution to the dilemma on this occasion has been to pass the buck to Riyadh.

According to Kirsten Fontenrose, former director for the Persian Gulf in the national security council, Trump is betting Riyadh will not want to be seen declaring war.

“The president knows that at the end of August when [deputy Saudi defence minister] Prince Khalid bin Salman was visiting Washington he told senior leaders at State, DoD [defence department] and the CIA that while they support economic squeezing the Iranian regime they do not support going to war. So the president knows that,” said Fontenrose, who resigned from the White House last November and is now at the Atlantic Council.

“So he’s probably looking at Saudi to say no no no – let’s handle this another way.”

Ellen Wald, a Gulf energy expert and author of a book about the Aramco oil company, Saudi, Inc, said Trump’s comments have exacerbated Riyadh’s dilemma.

“It really does put a lot of pressure on the Saudi monarchy to initiate a response, potentially a military response, and that’s probably really not something that Saudi Arabia is equipped to handle. The Saudi military is not prepared to fight a protracted war with Iran in any way,” Wald said.

Meanwhile, fighting a war on behalf of the Saudi regime has seldom been so unattractive in the US, following the murder of the Washington Post columnist Jamal Khashoggi and Trump’s own tweeted reminder on Monday, that the US is less dependent than ever on oil flows from the Gulf.

However, while it may be in nobody’s interests to go to war, the political costs for not responding currently fall most heavily on the Saudi crown prince, Mohammed bin Salman – and his response is unpredictable.

“We’re not dealing with common sense here. We are dealing with the fact that the Saudis have to retaliate one way or the other,” said Jean-François Seznec, a Gulf expert who teaches at Georgetown University. “Otherwise the position even of the crown prince would be seen as weak in the country and at this point he doesn’t have many friends even in his own country at the higher level.”

One option for Riyadh and Washington is a retaliation against a proportionate Iranian target, accompanied by much signalling that it is a limited response. However, Tehran may not see it that way.

“If they retaliate, the Iranians would have to retaliate even more. And we are just in an inertia of war,” Seznec said. “We really are in that situation right now and what’s so scary is that people all agree that this is not good for anybody. But there is nobody who can stop it.”