India, Aug. 23 -- The United States and Canada have repeatedly come close to a full-scale trade war since President Donald Trump returned to office. Trump has often stepped back from some of his strongest threats against Canada, but that period of relative calm has now ended.

New 50% US tariffs on certain Canadian goods took effect on Saturday, pushing the two countries closer to a possible tit-for-tat trade fight. Canada has threatened to respond with its own tariffs, raising fears that the dispute could hurt the US economy.

The new tariffs cover only a small part of the overall trade between the US and Canada. But economists warn that the impact could grow quickly if Canada retaliates and the Trump administration responds with even mo...