Donald Trump's decision to violate the Iran nuclear deal and reimpose US sanctions will not lead us immediately to disaster. That may come later.

Right now, America is on one side of the argument while its key allies including the UK, Germany and France, stand with Iran. Australia, by the way, also opposed scrapping the deal.

The leaders of the UK, Germany and France, say as a result of the deal "the world is a safer place". And, while Donald Trump seeks to hurt Iran economically, they are working with Iran to see what they can offer to keep the Iranians in the deal, "including through ensuring the continuing economic benefits to the Iranian people".

The most immediate effect of the US decision will be the re-imposition of sanctions against Iran's oil industry and its banking sector which will kick in over several months. The sanctions previously had a crushing effect on Iran's oil exports and since the nuclear deal was implemented oil exports have more than doubled.

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So make no mistake, they will cause a major financial hole which won't be easy for the Europeans to fill. And, in an increasingly integrated global economy, it's not easy to remain untouched by US sanctions.

A mini trade war?

Europe's leaders might convince the US to effectively exempt European companies from the sanctions regime. Or they could pass laws to protect their companies and claw back penalties imposed by the US by imposing tariffs on US goods.

To some, a mini trade war and division among key NATO allies on a crucial global security issue may already count as a disaster. But it could get worse.

Monthly crude oil and condensate exports from Iran 2012 to 2017. ( Source: EIA )

Iran says it will give those talks just a few weeks before it leaves the agreement and cranks up its uranium enrichment program.

It's worth remembering that, before Iran agreed to cut the program and mothball the machines at its heart it always denied it had a military dimension. But it built secret enrichment facilities and conducted experiments and made components that could be used to build a nuclear weapon.

That's why proponents of the deal signed in 2015 are so worried about scrapping it.

How sanction regimes leak

So, back on that path to disaster: if talks with the Europeans fail, a state that made substantial progress towards a nuclear weapon could kick out inspectors and press ahead, all the while maintaining its peaceful purposes.

And how would the world respond? It's worth remembering who buys Iran's oil. Last year 24 per cent of Iran's exports went to China, 18 per cent to India, 14 per cent to South Korea and 9 per cent to Turkey. Italy, France, the UAE and Japan are also significant customers.

The countries that import the most crude oil from Iran. ( Source: Clipper Data )

Without international consensus, sanctions regimes can be leaky, especially when major customers don't agree with them. That's another step down a perilous road.

Missiles are a sticking point

While America's allies are trying to negotiate their way through all this, they are also trying to reach agreement on what to do about Iran's ballistic missile program and its role in conflicts throughout the Middle East. And there are signs of real progress there.

But on the key question of what to do about the fact that, under the existing deal, caps on Iran's nuclear activity start to expire after 2025, there remains a major difference.

Donald Trump says that's unacceptable.

The UK, France and Germany only acknowledge that "a long-term framework … will have to be defined."

While that's not enough to satisfy Mr Trump it is enough to make the Iranians bridle at long-term European intentions.

The final destination

For now, Iran's pragmatic President, Hassan Rouhani, is centre stage in Tehran. Mr Trump's strategy relies on that remaining the case, even if the deal falters, giving him time to bring the Europeans around and convince the Iranians that the renewed financial pain isn't worth it.

Sorry, this video has expired Iranian President says nuclear deal negotiations to restart

Most arms control experts in the west agree it would be good to have a permanent cap on Iranian nuclear activity and many US allies want to see Iran's missile capability reined in and its role in the region curtailed. But Mr Trump's dramatic step, with no alternative in place, is so far, all promise and no plan.

Meanwhile, Iran could flex a bit of nuclear muscle by resuming some activity, while blaming the US and trying to keep the agreement alive.

The hardcore Islamic Revolutionary Guard Corps, which welcomed the billions that flowed into Iran when sanctions were lifted but has always been critical of limiting its nuclear ambitions, could even push for the full-blown, open pursuit of nuclear weapons.

On the road to disaster, that's pretty much the final destination.

Lessons for North Korea — and Iran

In announcing his government's response to the US decision, Mr Rouhani alluded to Mr Trump's current attempts to strike a deal with North Korea, warning the US has shown it can't be trusted.

Mr Trump even mentioned his Secretary of State was jetting to North Korea as he wrapped up his announcement on Iran.

In his view, tough talk has forced them to discuss full de-nuclearisation.

But the North Koreans already have a nuclear weapon and Iran's Revolutionary Guard Corps may be learning a different lesson: you have a better chance of dealing with the likes of Donald Trump if you already have a big stick.