Tense relations between historic allies have led to the imposition of tariffs. The United States is applying a 50% tariff to $20 billion worth of Canadian products. This move follows the failure of last-ditch negotiations to resolve the latest strain in relations.

Further details on this development are available from the source. The tariffs are part of a trade action that affects a significant amount of Canadian products. Canada has announced plans to retaliate against the tariffs.

The situation is a result of failed negotiations, and the impact of the tariffs and Canada's retaliation is not fully outlined in the available information. For more on this trade action and its implications, readers can consult the source.