Bilateral trade talks have broken down as Ottawa says it would retaliate and match US tariffs affecting US$20 billion of Canadian goods.

Canadian Prime Minister Mark Carney vows to retaliate, says his country recognized that 'America has changed' and that the two countries would 'not return to our old relationship'

The United States is imposing 50% tariffs on $20 billion worth of Canadian products after last-ditch negotiations failed to resolve the latest strain in already tense relations…