Well, that was quick.  Not yet in the White House, Donald Trump is already threatening to impose sweeping new tariffs on Mexico, Canada and China.  He said trade tariffs – which can be imposed by a presidential executive order – were necessary to punish the three governments for aiding criminal gangs. Mexico and Canada would be hit with a 25 per cent tariff on all imports, with Trump adding that China risks a further 10 per cent on existing tariffs. The move was surprising in its timing but not in its substance. Trump made tariffs a mainstream issue during his…