Michigan Supreme Court Weighs Future of Line 5 Oil Pipeline

The cases could determine whether Enbridge's planned tunnel project will go forward.

Mar. 12, 2026 at 2:20am

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The Michigan Supreme Court heard arguments in a set of cases that could impact the future of the Line 5 oil pipeline. The questions before the court could determine whether the proposed tunnel project will move forward as planned or if operators will need to restart parts of the approval process. Enbridge, the pipeline operator, is pushing for a speedy resolution to the challenges, acknowledging that Line 5 operating without a protective tunnel poses an environmental risk to the Great Lakes.

Why it matters

The future of Line 5 has been a contentious issue in Michigan, with environmental groups and tribes pushing for the pipeline's shutdown or decommissioning, arguing it poses an unnecessary risk to the safety of the Great Lakes. The outcome of these cases could have significant implications for the state's energy infrastructure and environmental protections.

The details

Enbridge is arguing that the tunnel project is the safest option to continue operating Line 5, while opponents argue that the continued operation of the pipeline could pose an environmental threat for decades to come. The state's Public Service Commission previously approved the tunnel project, saying it presented the safest and most feasible option for the pipeline to still operate.

  • The Michigan Supreme Court heard arguments on the cases on Wednesday, March 11, 2026.
  • Enbridge says the construction of the tunnel is set to take 5 or 6 years.
  • The case before the U.S. Supreme Court, regarding whether the case brought by Michigan Attorney General Dana Nessel should be heard in state or federal court, was argued last month.

The players

Enbridge

The operator of the Line 5 oil pipeline, pushing for a speedy resolution to the challenges and acknowledging that Line 5 operating without a protective tunnel poses an environmental risk to the Great Lakes.

Michigan Tribal Governments

A group challenging the cases, arguing that the ongoing transport of oil through the Great Lakes presents a risk to Michigan's economy and natural resources.

Environmental Advocates

A group challenging the cases, arguing that the continued operation of the pipeline could pose an environmental threat for decades to come.

Michigan Attorney General Dana Nessel

Involved in a separate case before the U.S. Supreme Court regarding whether the case brought by Nessel should be heard in state or federal court.

Michigan Public Service Commission

Previously approved the tunnel project, saying it presented the safest and most feasible option for the pipeline to still operate.

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What they’re saying

“Ironically, it's the pipeline company that has the most pro-environment position here, because we want to do everything we can to eliminate that .001% anchor strike risk — and they want to do everything that they can to perpetuate it. It doesn't even make sense.”

— John Bursch, Attorney for Enbridge

“They join this proceeding to protect those resources, alleging that the proposed project is likely to have the effect of polluting, impairing and destroying natural resources by prolonging and increasing the risk of an oil spill for decades.”

— Adam Ratchenski, Attorney for the Little Traverse Bay Bands of Odawa Indians

“If the tunnel is authorized without appropriate consideration for public trust concerns, we could very well be handing to the next generation another environmental catastrophe.”

— Riyaz Kanji, Attorney for Flow Water Advocates

“If the permit is denied, Enbridge will keep operating the pipeline on the straits lake bed indefinitely — contrary to what everyone wants. We want to eliminate that .0001% chance of an anchor strike — but the reality is that it will continue to operate.”

— John Bursch, Attorney for Enbridge

“No one wants to keep the Great Lakes ecosystem free of any impairments more than the federal government and, frankly, Enbridge itself. We don't want to have an accident there, and so that's why we want to put it in the protective tunnel.”

— John Bursch, Attorney for Enbridge

What’s next

The Michigan Supreme Court, which is controlled 6-1 by liberal justices, will issue a ruling on the cases that could determine the future of the Line 5 pipeline and the proposed tunnel project.

The takeaway

The future of the Line 5 pipeline has become a contentious environmental and economic issue in Michigan, with Enbridge arguing the tunnel project is the safest option to continue operations, while opponents contend the pipeline poses unacceptable risks to the Great Lakes. The Michigan Supreme Court's ruling will have significant implications for the state's energy infrastructure and environmental protections.