They accused the company of flouting the law and endangering the world's largest freshwater system.
A shutdown of Line 5 "raises substantial federal and worldwide questions relating to interstate and global commerce", which is why the case is before a federal judge and mediation has been ordered, Enbridge said.
There's also a risk of interstate energy emergencies, the brief notes - a phenomenon already on display in several East Coast states as a result of the ongoing shutdown of the Colonial pipeline, a key energy artery that was targeted by a foreign cyberattack.
The road to this critical moment began in 1953. A 645-mile petroleum dual pipeline system, it runs under the Straits of Mackinac from Superior, Wis., to Sarnia, Ontario, by way of MI.
As of Wednesday evening, Enbridge was still pushing 23-million gallons of crude oil and natural gas liquid a day through the pipeline. The line stretches from Wisconsin through MI over to Sarnia, Ontario.
Another Enbridge pipeline caused a massive spill into the Kalamazoo River in 2010.
It's one of the largest inland spills in USA history, and cleanup still continues today.
Canada Warns Michigan Oil Line Shutdown Could Undermine US Ties
Litigation could drag on until at least 2024, said Joe Comartin, Canada's consul general in Detroit who is arguing on behalf of Ottawa.
The implications of the governor's energy pipeline shutdown, focusing on the risks and burdens to other state's and nation's energy security, economies, and the environment. The footage and the board found damage to the pipeline's protective coating and anchor damage from passing commercial vessels.
Political "brinksmanship" in MI risks allowing Enbridge Inc.to abandon plans for a $500-million tunnel that would protect an ecologically sensitive Great Lakes waterway from the controversial Line 5 pipeline, business leaders warned Wednesday.
Then, in 2019, a changing of the guard.
Whitmer's office said in a statement that the Colonial Pipeline interruption "shows the danger of relying heavily on a single energy supply. The Landlord has decided that Enbridge is a threat to their property", said David Holtz, environmental advocate with Oil and Water Don't Mix.
One gas industry expert says shutting down a controversial oil and gas pipeline in MI would lead to a major increase at the pumps north of the border. "We are in full support of the Canadian government filing a brief to try to continue mediation between Enbridge and the State of MI".
"If the state prevails in the underlying litigation, Enbridge will face the prospect of having to disgorge to the state all profits it derives from its wrongful use of the easement lands following that date".
There's still a battle over whether this case belongs in federal or state court, that likely won't be resolved this week. Separately, the judge responsible for the case has ordered the parties to work with a neutral mediator to explore a potential global resolution of the case.