The celebrated French economist Thomas Piketty does not mince his words when it comes to US President Donald Trump and his trade war with China.

Sitting down for a recent interview with the South China Morning Post, the darling of the global left said Trump was using the tariff dispute to mask a far bigger problem in the world’s biggest economy: an unyielding class divide.

The celebrity economist cautioned the left against despair at Trump and other populist leaders using identity politics and protectionism to galvanise the poor.

Instead, he said the likes of Bernie Sanders in the US and Jeremy Corbyn in Britain must continue advocating policies such as increased income tax for the wealthy – even if it earns them brickbats in the short term.

“The trade war was largely invented by the Trump administration for their own political strategy,” Piketty said in the interview this month.

The author of the 2013 economic treatise Capital in the Twenty-First Century was in Hong Kong to deliver a lecture jointly organised by the Education University of Hong Kong and the French consulate.

“To me the main risk is not so much the trade war but the class war in the sense that the main policies Trump has been conducting are more class-war policy rather than a trade-war policy,” Piketty said, referring to Trump’s promises to reduce taxes for the wealthy.

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This week, the US president said he planned to cut income tax for “middle-income people” by 10 per cent – a move that comes on the back of last December’s sweeping tax reform that slashed corporate taxes from 35 per cent to 21 per cent.

Piketty said Trump’s strategy was to use external threats – China in the case of the trade war – to gain support from the poor, when it was in fact his “pro-rich” policies such as tax cuts and protectionism that were hurting them the most.

“The easy solution when you are a populist leader, if you want to take advantage of rising inequality, is you tell the poor people who are not benefiting from globalisation – well look, these are the foreign workers who are to be blamed, foreign countries are to be blamed, China is to be blamed,” he said. “You can always find others to blame, but that is not the solution.”

Increasing taxes for the wealthy and increasing the share of public wealth were two policies that countries must seriously consider, Piketty said, arguing that they should not be seen as extreme left economic agendas.

It was untenable, he said, that in the West public wealth was a negative proportion of total wealth – meaning public debt was higher than the total value of public assets.

In China, the total net value of public property stands at around 30 per cent of total national wealth, Piketty said.

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While the Chinese level may be too high, countries must strike a balance, he said.

Piketty had biting words for the world’s richest individuals too. He frowned on billionaires who pushed back against higher taxes by claiming they would give back to the public out of their own volition, through philanthropy.

The problem with this was that, under the guise of “returning” the money, the rich could buy favourable media coverage and political influence, he said.

International economic organisations such as the Organisation for Economic Co-operation and Development (OECD) and the International Monetary Fund could do more to make societies more progressive too, Piketty said.

He poured scorn on the OECD’s advocacy of indirect sales taxes over direct income tax.

“I am a bit angry sometimes with what the OECD, IMF and World Bank and other organisations say,” said Piketty. “They still have the old tax agenda of only pushing for indirect taxation or sales tax.”

The imposition of goods and services taxes (GST) in places such as India and Malaysia has proved controversial because of the prevailing view that these levies disproportionally tax lower income groups.

In Malaysia, the GST is widely seen as one of the major issues that toppled the former prime minister Najib Razak in the country’s May elections.

Piketty urged the West to resist increased sales taxes, too.

Meanwhile, progressive leaders such as Sanders and Corbyn need to keep plugging away at exposing the perils of the protectionist and “anti-globalisation” agenda of Trump and his ilk, the economist said.

“We need to explore the middle way … We should not be impressed by the general discourse that this is the end of the world, this is the end of everything,” he said. “There will be other transformations, there will be developments beyond free-market capitalism.”