New Delhi, Feb. 3 -- The bite of Donald Trump's trade policy, many had hoped, would be a whole lot softer than its bark. The US president, it would appear, is not sorry to dash those hopes. Invoking a national emergency, he has imposed tariffs-effective this week-of 25% on imports from Canada and Mexico, except for oil and gas from Canada, on which he has levied an import duty of 10%.

A levy of 10% has also been slapped on imports from America's biggest trade partner, China. Retaliatory tariffs are underway. Canada is gearing up for national elections, and no leader can afford not to be seen standing up to a bully south of the border. Canada has announced 25% tariffs on imports from the US worth $155 billion, including Tesla electric car...