Donald Trump, in announcing his sweeping new tariffs on US imports on Wednesday, promised that the history books would record 2 April as America's "liberation day".

After two days of stock market turmoil, however, this may also be remembered as the week the president's second-term agenda ran headfirst into economic - and political - reality.

US stocks have been in a tailspin since Trump unveiled his tariffs at Wednesday afternoon's White House Rose Garden event, with signs that America's trading partners - Canada, the European Union and China, most notably - are not backing away from a fight.