In a sharp escalation of global trade tensions, Canada has begun imposing a 25% tariff on select vehicle imports from the United States, joining China in retaliating against a new wave of protectionist measures introduced by President Donald Trump.

President Trump added onto an already complex tariff picture. Here is how Wednesday's new levies will affect countries differently: China China is essentially in its own bucket. Trump, since beginning his second term,

The European Union is deepening other trade partnerships as U.S. relations sour. But with China, the relationship could get closer — or more combative.