The premier of Ontario is about to discover Enbridge's Line 5.

Doug Ford has repeatedly floated using Alberta's oil exports as leverage in Canada's trade dispute with the United States. But critics say the strategy ignores a key reality: Ontario relies on the same cross-border pipeline system to fuel its own economy.

The proposal to restrict Alberta crude exports is intended to put pressure on American refiners. 

Ford calling again to block oil, potash exports to U.S. in trade war gets cold response https://t.co/7rBgQIvLZY pic.twitter.com/HLOLHCERkN

— National Post (@nationalpost) July 22, 2026

However, much of the oil that reaches Ontario first travels through the U.S. before returning to Canada via Enbridge's Line 5 pipeline.

Line 5 transports up to 540,000 barrels of crude oil and natural gas liquids per day from Wisconsin, across Michigan and into Sarnia, Ontario. According to Enbridge, the pipeline supplies roughly half of the oil consumed in Ontario and Quebec, while Western Canadian crude accounts for approximately 77% of Ontario's refinery feedstock.

That makes the pipeline one of Ontario's most important pieces of energy infrastructure.

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Michigan has been trying to shut down Line 5 since 2020, arguing the pipeline poses environmental risks in the Straits of Mackinac. 

The pipeline remains in operation while the courts consider the case, and a replacement tunnel intended to secure its future is not expected to be completed before 2031.

Escalating an energy confrontation with Washington could increase the political risk surrounding Line 5. If the pipeline were disrupted, Ontario could face significant reductions in crude oil supplies for its refineries, resulting in higher fuel costs and supply challenges for millions of residents.

Danielle Smith "What I would say is you have to, if you have to be very careful not to put things on the table that you're not prepared to do."

"And I'm going to try to prevent Canada from making a very dumb decision of putting energy on the table because line five goes… pic.twitter.com/l96PYmflaC

— cbcwatcher (@cbcwatcher) July 24, 2026

Alberta Premier Danielle Smith has consistently rejected proposals for an oil export tax or export restrictions, calling the idea a "non-starter" and warning that using Canadian energy as a political weapon would hurt Canadians alongside Americans.