It was meant to last four weeks, a swift campaign to cripple Iran’s nuclear ambitions and force regime change.

Five weeks on, the White House is struggling to find a way out of a conflict that has inflicted much greater economic pain than it bargained for.

In the days before the bombing of Tehran began, Donald Trump was buoyant.

Fresh from what aides cast as extraordinary military success – a daring raid to capture Nicolás Maduro, the Venezuelan leader – the president and his generals were convinced Tehran would buckle in a similar fashion.

The plan was simple: hit hard, hit fast, and Tehran would have no choice but to submit to Washington’s demands.

But the opposite has happened. Bolstered by the success of its missile strikes and intimidation of Gulf neighbours, Iran turned its missiles on the Strait of Hormuz, bringing the global shipping lane to a standstill. Iran’s stockpile of uranium, the fuel needed to build a nuclear weapon, remains in the regime’s hands.

At the same time, oil prices have soared, major airports fear fuel shortages and the cloud of sustained economic harm hangs over a president facing a difficult midterm election and falling approval ratings.

“They [the administration] underestimated it, they were shocked by the response from Iran,” a senior Gulf diplomatic source said.

“The question is: do they care? They don’t seem to care about the global economic impact, they care about the domestic impact. If they can control the oil, they can present it as a win to the American people, like Venezuela,” the source added.

Mr Trump’s options seem limited. Down one path is a fast-escalating conflict that could put US troops on the ground and push the world’s economies towards global recession. The other – an un-Trumplike retreat – could be humiliating.

The Pentagon has drawn up plans for a weeks-long invasion, including potential raids on Kharg Island, Tehran’s main oil export hub, and attacks on coastal sites near the Strait of Hormuz. The 31st Marine Expeditionary Unit, including about 2,200 troops, arrived in the Middle East over the weekend in preparation.

Another force – the 11th Marine Expeditionary Unit – is expected to arrive soon. And 3,000 paratroopers from the 82nd Airborne Division have also been ordered to the region. They are trained to carry out helicopter assaults behind enemy lines and seize critical infrastructure.

If operations are launched, it will be expensive monetarily and, in all likelihood, in terms of dead American servicemen. The high costs of a military battle for the president, who had campaigned to end foreign wars, have given the White House reason to rein in a conflict that has spiralled out of control and could get much worse.

And so, the administration appears to be adjusting its objectives. Mr Trump is said to have told aides privately that he’s willing to end the conflict even if the strait remains largely closed, likely extending Tehran’s grip on the shipping lane.

Instead, he increasingly wants Britain, and other Nato allies, to be responsible for reopening the strait.

“All of those countries that can’t get jet fuel because of the Strait of Hormuz, like the United Kingdom, which refused to get involved in the decapitation of Iran, I have a suggestion for you,” Mr Trump wrote on Truth Social on Tuesday.

“Number 1, buy from the US, we have plenty, and Number 2, build up some delayed courage, go to the Strait, and just TAKE IT.”

He added: “You’ll have to start learning how to fight for yourself, the USA won’t be there to help you any more, just like you weren’t there for us. Iran has been, essentially, decimated. The hard part is done. Go get your own oil!”

Amid the anger, a climbdown has been coming.

On Monday, Karoline Leavitt, the White House press secretary, omitted reopening the strait as a key priority to ending the war.

“The full reopening of the strait is something the administration is working towards, but the core objectives of the operation have been clearly defined for the American people by the Commander-in-Chief,” Ms Leavitt told reporters.

There is just one problem, of course: a peace deal requires Iran to negotiate. Mr Trump insists the US is having “serious discussions” with a “new and more reasonable regime in Tehran” in talks led by Pakistan. Iran, however, insists no direct talks are happening.

The need for peace is not lost on some of the president’s most loyal supporters. “Our ‘allies’ depend on the strait as their lifeline for energy – yet they neither have the forces nor the will to step in,” Steve Bannon, the president’s former chief strategist, told The Telegraph. “The fact that they are not coming in any meaningful way is just starting to sink in – it’s a terrible betrayal, one not lost on the American people.”

Regardless, America’s own military is showing its limitations. Iran has chosen to leverage its ability to create a costly, long-term war by continuing to disrupt global energy supplies and has threatened more instability in the Middle East.

“For the Iranians, the longer this war goes on, the better. They can leave the conflict with more demands,” the Gulf diplomatic source said.

Britain has a similar, increasingly gloomy view. “There was a sense a few weeks ago that Iran was desperate for an off-ramp. The problem with Trump’s rhetoric is that the Iranians now feel buoyant and upbeat,” a Whitehall source said.

The truth behind the negotiations Mr Trump continues to tout remains murky. But what is clear is the impact the war is having on global oil prices and, in turn, the president’s approval rating.

By the start of the 32nd day of the war on Tuesday, Brent crude oil hit $118, up 59 per cent from 12 months ago. Mr Trump’s approval rating fell in recent days to its lowest point since he returned to the White House.

The four-day poll, completed on Monday, showed that 36 per cent of Americans approve of the president’s ‌job performance, down from 40 per cent in a Reuters/Ipsos poll conducted last week.

In what is perhaps the most telling figure, just 25 per cent of respondents approved of Mr Trump’s handling of the cost of living, an issue that was at the centre of the 2024 presidential election campaign that capped his remarkable return to the White House.

For a president obsessed with his approval ratings, an end to the war may come sooner than he planned.