Michigan Court Deals Blow to Enbridge Line 5 Tunnel

The Michigan Supreme Court has thrown out the state regulator’s approval of Enbridge’s plan to encase its Line 5 pipeline in a tunnel beneath the Straits of Mackinac. In a unanimous decision, the court held that the Michigan Public Service Commission (MPSC) overstepped its statutory authority by approving the project, which the commission had deemed a public utility necessity. The ruling effectively resets the regulatory clock for the controversial pipeline, which carries oil and natural gas liquids through the Great Lakes region.

For Wisconsin readers, the decision carries weight beyond Michigan’s borders. Line 5 runs through the Bad River Band of Lake Superior Chippewa’s reservation in northern Wisconsin, where the tribe has fought to shut down the pipeline due to corrosion and easement disputes. The Michigan ruling strengthens arguments that state regulators cannot simply rubber-stamp infrastructure projects that pose environmental risks to tribal lands and shared waters. Legal experts note that the decision may influence pending federal cases and state-level reviews in Wisconsin, where the pipeline’s route crosses sensitive watersheds.

What the Ruling Means for the Region

The court’s reasoning centered on the MPSC’s limited jurisdiction. The justices concluded that the tunnel project—a concrete casing built to protect the pipeline—does not qualify as a “public utility” under Michigan law, as it serves only Enbridge’s private commercial interests. This narrow interpretation could set a precedent for challenging similar pipeline projects across the Midwest, where regulators often approve infrastructure under broad public interest claims. Environmental groups and tribal nations have long argued that such approvals bypass thorough environmental review.

The tunnel project, estimated to cost hundreds of millions of dollars, was Enbridge’s proposed solution to the risk of an oil spill in the Straits. But the court’s decision leaves the pipeline’s future uncertain. Enbridge has vowed to continue operating Line 5 under existing permits while exploring legal options. For the Bad River Band and other Wisconsin tribes, the ruling is a vindication of their stance that pipeline safety cannot be left to regulators with limited oversight. The Daily Badger Bulletin will continue to track how this decision shapes energy policy and tribal sovereignty in the Badger State.