More: And although the money itself belongs to Iran " the funds are frozen under sanctions " it would be a solution for Mr Trump, who broke his campaign promise and led America to war on Feb 28.

With no country other than Israel by his side militarily, and without any public or diplomatic backing from traditional allies, the US president promised that overwhelming force would bring a swift victory and prevent Iran from obtaining a nuclear weapon.

Instead, with higher oil prices and the chances of a global recession higher than at any time since the 2020 pandemic, peace will probably mean releasing those billions in cash to a regime that, despite Mr Trump's numerous promises and declarations, remains standing.

For the White House, the problem is not only the scale of the payment. It also sends a contradictory and electorally risky message to American voters as Washington's political calendar turns from war into a midterm election cycle.

For starters, the cash does not return a fully fledged peace agreement but something closer to a vague one-page document that provides "the framework for future negotiations".

If that is indeed the case " and statements from both sides in the conflict seem still very much at odds " it will be an endpoint a long way from Mr Trump's starting point.

Announcing the beginning of the war from Mar-a-Lago, his Florida home and resort, the president pledged to destroy Iran's missile industry and eliminate regional terrorist proxies. He also urged the Iranian people to rise up and overthrow the regime.

Yet the one-page outline agreement appears to address none of those objectives, instead leaving them to be discussed during the 30 to 60-day period that is expected to follow. Indeed, on Monday, the president watered down his original demand that Iran's highly enriched uranium be handed over to the United States.

Releasing billions of dollars is as legally difficult as it is politically complex. Just $2bn (1.6bn) of Iran's assets are thought to be frozen in the United States. Much of the remaining money, calculated to be worth about $100bn (80bn), is held in international bank accounts frozen by the United Nations.

To release it, Washington would probably need to waive sanctions, cooperation from foreign governments and a mechanism to guarantee the cash not used by the regime to rebuild its nuclear weapons programme or fund its proxies.