Canada Warns Michigan Oil Line Shutdown Could Undermine US Ties

General view of the Imperial Oil refinery, located near Enbridge's Line 5 pipeline, which Michigan Governor Gretchen Whitmer ordered shut down in May 2021, in Sarnia, Ontario, Canada, on March 20, 2021. Carlos Osorio/Reuters

CALGARY, Alberta—A day before Michigan’s deadline to close down a key crude oil pipeline, Canada on Tuesday issued its strongest remarks so far about the move, warning that it could undermine relations with the United States, its closest ally and trading partner.

Canadian company Enbridge Inc is preparing for a legal battle with Michigan and courting protests from environmental groups, betting it can ignore the state’s Wednesday deadline to shut down Line 5, which runs under the Straits of Mackinac.