Donald Trump, Xi Jinping and the meeting looming over Middle East war

Donald Trump said last month that his planned visit to China on March 31 would be "a wild one".

"We have to put on the biggest display you've ever had in the history of China," he said.

A lot has changed since that confident declaration on February 20. Most of it has weakened the US president's position.

Hours after he spoke, the US Supreme Court ruled most of the tariffs he had been using to try to influence world affairs were illegal. China, in particular, had been a target of his wrath when it came to those.

One week later, Trump ordered the US to join Israel and launch military attacks on Iran. Since then, it's become clear that any hopes that the war would be over quickly are gone.

Fighting and aerial attacks continue to engulf the Middle East. Global oil prices are spiralling.

The developments since February 20 mean that, if Trump were to travel to China as planned, he would be doing so with a legal cloud hanging over his favoured form of diplomacy: tariffs.

But perhaps more significantly now, his chances of turning up in Beijing with the ability to assert and exude power over the United States's great rival after a decisive military victory in Iran are also slim.

And there is also the international rebuff he has faced over his demands that other countries must help the US force open the Strait of Hormuz.

Which means there are at least three good reasons why Trump shifted on Monday, saying he had asked his hosts if they could "delay" the visit by "a month or so".

"I'd love to [go], but because of the war, I want to be here," Trump said in Washington. "It's very simple. I have got a war going on."

He initially implied on Sunday that his telegraphed decision to postpone the summit was linked to Beijing's refusal to get involved in clearing the strait.

Then he and his officials moved away from that and said it was just because he had a war to run.

Iran's control and effective blockading of the strait have set in motion a series of economic, social and diplomatic dominoes around the globe that go far beyond steep increases in oil prices and the slashing of global supply.

In India, the Financial Times reports, crematoriums have stopped using gas to burn bodies, and restaurants have stopped deep-frying food.

In Pakistan, civil servants are working a four-day week, and in Bangladesh, universities have shut and exams have been cancelled.

Those moves are reflections of South-East Asia's heavy reliance on gas — which also ships from the Gulf, the narrow stretch of water through which 20 per cent of the world's oil travels, along with significant quantities of gas and other exports.

Other countries that rely overwhelmingly on bottled gas for cooking are also running low.

Blocking the strait has created huge dilemmas — and economic dislocation — for economies across the globe that must adjust to the price shock, the supply cut and the questions of what self-interest suggests they do about it.

But the various threads of the considerations it prompts for countries around the world are perhaps nowhere near as complex as they are for China.

Analysts have claimed there is a heavy weighting of superpower competition to Trump's decision to strike Iran, among the various reasons he and his officials have put forward.

Just as the move to control Venezuela and its oil was seen as an economic and resources strike against China, a move to either seize control of Iran's oil output — or even just deprive Iran of being able to access it — has been seen as a key part of the Trump play.

And the spectre of being able to turn up in Beijing holding that card in his hand must have looked pretty good.

But it is a bit more complicated than that, as it turns out. China is the dominant buyer of Iran's oil, purchasing roughly 90 per cent of its output.

Trump might say China is one of the countries that has an interest in unblocking the strait. But Iran has been letting through ships bound for China with Iranian oil on board.

The co-founder of TankerTrackers.com, Samir Madani, told CNBC last week that Iran had sent 11.7 million barrels of crude oil to China through the waterway since the war began, according to vessel-tracking data.

"The Strait of Hormuz is open," Iranian Foreign Minister Abbas Araghchi has insisted. "It is only closed to the tankers and ships belonging to our enemies, to those who are attacking us and their allies. Others are free to pass."

Some Indian vessels have been allowed to pass through the strait, along with a Turkish-owned vessel, last week after Ankara reportedly negotiated passage directly with Tehran.

So while China's export-reliant economy will be hurt if the oil shock causes a global downturn, it is not as badly affected, at this stage, by the strait's closure as Japan, India, South Korea and Europe are.

In fact, on Monday, China stressed it had enough energy resources to weather disruptions for the foreseeable future.

That's yet another reason why some analysts believe Trump is seriously considering attacking the oil infrastructure on Iran's major export hub, Kharg Island.

It doesn't make sense to destroy all that oil production and export capacity if you want to control it yourself.

On the other hand, if your aim is simply to deprive someone else of that control, it makes a bit more sense.

While a Kharg Island attack has been considered and dismissed as folly by various US administrations for decades, Trump has already ordered the bombing of military targets on the island, and said on the weekend the US might strike it again "just for fun".

Trump might like to control it as a way of controlling Iran. But if he can't achieve that, his actions to date mean there is no reason to think he would not destroy it to destroy the Iranian economy, and to try to cripple China.

If China isn't threatened as much as other countries by the Gulf's closure, Trump's hopes of maximising leverage over Xi Jinping fade pretty quickly.

Everyone has their own interests in the strait

There are an almost infinite number of other threads involved in the story of the Strait of Hormuz now.

For starters, it is hard not to think of some world leaders sitting, gobsmacked in their quieter moments, about the gall of the US president asking them to help in a war which is illegal under international law, about which they were not consulted, and which the United Nations has not met to discuss.

Equally, as the war entered its third week, NATO countries must have been astonished at his demand that they come to his aid or face "a very bad future", given Trump's dismissal of the alliance and his refusal to assist it directly in supporting Ukraine.

"If there's no response or if it's a negative response, I think it will be very bad for the future of NATO," he told The Financial Times in a short interview on Sunday.

By Monday, Trump was both complaining that some countries had rejected his demands that they help and insisting that some unspecified countries would be coming on board.

But close US allies, including Australia, Germany, Greece, Italy and others have said they don't want to get involved in patrolling the strait, where shipping is vulnerable to land-based weaponry and anything Iran might put on or under the water, because it's so narrow.

There have been reports that France and Italy have asked Tehran about separate deals to have their shipping needs met, though both countries have insisted they were only sounding out the Iranian regime as part of the European bloc.

All this seems to have led to quite a change of tone from the US president.

Suddenly, Trump wanted the backing of a coalition. Only a week ago, he had told British Prime Minister Sir Keir Starmer not to bother sending two aircraft carriers to the region because "we don't need them any longer".

He said: "We don't need people that join Wars after we've already won!"

Whatever quantities of gall may be attached to the US president's demands, every country will be considering its own strategic interest.

Certainly, many of them have an interest in the Gulf being opened and the perilous state of the global economy being stabilised.

But beyond the great risks to naval vessels — and their crews — that might be sent to the Gulf is the significant dilemma that such an engagement would inevitably draw them into a war in which most countries don't want to engage.

Trump has boasted regularly that the US, now the world's largest oil producer, will not run short of gas, but it is also true that this war has disrupted many of his other global plays.

It has proved to be of immense benefit to Russia, which is enjoying a windfall for its coffers from a higher oil price and reduced US sanctions against Russian oil to ease the global shortfall.

On Wednesday, stories emerged suggesting the US may ease sanctions on Venezuela in the interests of getting more oil flowing.

The choked Strait of Hormuz is not just disrupting world energy markets and hurting US allies; it is also undermining Trump's own plans.

Laura Tingle is the ABC's Global Affairs Editor.