Why Trump is hitting China on trade - and what might happen next

Suddenly, Donald Trump's trade war is in much sharper focus.

Rather than a fight on all fronts against the world, this now looks far more like a fight on familiar Trumpian territory: America v China.

The 90-day pause on the higher "retaliatory" tariffs levied on dozens of countries still leaves a universal across-the-board tariff of 10% in place.

But China – which ships everything from iPhones to children's toys and accounts for around 14% of all US imports – has been singled out for much harsher treatment with an eye-watering rate of 125%.

Trump said the increase was due to Beijing's readiness to retaliate with its own 84% levy on US goods, a move the president described as showing a "lack of respect".

But for a politician who first fought his way to the White House on the back of an anti-China message, there is much more to this than simple retaliation.

For Trump, this is about the unfinished business of that first term in office.

"We didn't have the time to do the right thing, which we're doing now," he told reporters.

The aim is nothing less than the upending of an established system of global trade centred on China as the factory of the world, as well as the once widely held view that underpinned it – the idea that more of this trade was, in and of itself, a good thing.

To understand just how central this is to the US president's thinking, you need to go back to the time before anyone ever thought of him as a possible candidate for office, let alone a likely winner.

In 2012, when I first reported from Shanghai - China's business capital - increased trade with the country was seen by almost everyone – global business leaders, Chinese officials, visiting foreign governments and trade delegations, foreign correspondents and learned economists – as a no brainer.

It was boosting global growth, providing an endless supply of cheap goods, enriching China's army of new factory workers increasingly embedded in global supply chains, and providing lucrative opportunities to multinational corporations selling their wares to its newly minted middle classes.