If the US genuinely tries to close its overall deficit with big tariffs all round, it will cause a crunching recession. If Trump discriminates between trading partners, the heavily tariffed ones can nip through the side door of those who escaped more lightly.

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Donald Trump is planning reciprocal tariffs on countries that impose duties on U.S. imports, heightening fears of a global trade war. The tariffs are expected to impact industries reliant on metal imports.

An index of global shares was lower on Wednesday, pressured by choppy trading on Wall Street and a dip in European stocks, as U.S. President Donald Trump's latest tariff threats on auto, semiconductor and pharmaceutical imports injected a sense of caution into the markets.