TORONTO — Roughly $900 billion in annual trade between Canada and the United States — and with it, traditionally chummy bilateral ties — is on the brink of upheaval, with President Donald Trump threatening to impose sweeping tariffs on Canada as early as this weekend.

Canada's federal government has assured Alberta that it will not bear a disproportionate burden of any retaliatory tariffs imposed in response to potential US import levies.

Chrystia Freeland, the former finance minister who is running to replace Justin Trudeau as Canada's prime minister, says her country needs to release a "retaliation list" of goods the country would target if U.