That leverage came from the singular importance of the US market to the global economy. Trump’s personal belief in the utility of tariffs – and willingness to let them go into place and then, if necessary, escalate to shut down any retaliatory efforts – only served to enhance that reality.

U.S. President Donald Trump's tariff decisions since he took office on January 20 have shocked financial markets and sent a wave of uncertainty through the global economy. Here is a timeline of the major developments: February 1 - Trump imposes 25% tariffs on Mexican and most Canadian imports and 10% on goods from China,