Michigan's highest court dealt a significant setback to Enbridge's planned pipeline tunnel beneath the Great Lakes, ruling 6-1 that state regulators failed to address critical environmental and public trust concerns before approving the project.
The Michigan Supreme Court on Friday ordered the Michigan Public Service Commission to go back and reconsider the permit it granted in 2023 for a tunnel that would carry the Line 5 oil pipeline under the Straits of Mackinac, the narrow passage where Lakes Huron and Michigan meet. The court found regulators fell short on three separate grounds, any one of which would have been enough to send the permit back for a second look.
Four Michigan tribal nations and several environmental groups had sued after the commission approved the tunnel. The court agreed the commission never adequately considered whether building a tunnel would effectively extend the lifetime of the 73-year-old pipeline and produce more long-term environmental harm. Regulators also failed to apply a consistent standard when comparing the pipeline to alternatives like trucks or trains for moving oil. And the commission never assessed how tunnel construction and operation might affect fishing, boating, and other public trust rights on the Great Lakes, CBS News reported.
That last point matters. The Straits of Mackinac are not just an industrial corridor. The tribes that brought the lawsuit consider the straits a sacred site for the Indigenous Anishinaabe people. A 4-mile segment of Line 5 currently sits on the bottom of the straits, and Enbridge proposed encasing it in a concrete tunnel to reduce the risk of a spill.
Enbridge first proposed the tunnel roughly a decade ago, around the same time a ship anchor dented part of the pipeline. The Canadian energy company pitched the tunnel as a safety upgrade that would protect the Great Lakes while keeping oil flowing from Superior, Wisconsin, to Sarnia, Ontario.
The Michigan Public Service Commission agreed and granted the construction permit in 2023. But the tribal nations and environmental groups moved quickly to challenge it in court, arguing that regulators had rubber-stamped the project without doing the hard work of weighing its full consequences.
Friday's ruling validates that challenge. Only one justice dissented from the 6-1 majority, though the court's opinion did not fully block the tunnel, it sent the permit back for reconsideration. Whether the commission can fix the deficiencies the court identified, or whether the project collapses under the weight of its own regulatory failures, remains an open question.
David Gover, an attorney with the Native American Rights Fund, made clear the tribes see no version of this project that works. He issued a statement after the ruling:
"Whether Line 5 is suspended in the water or encased in a tunnel, it is simply a terrible idea to pump more than half a million barrels of oil every day through the middle of the Great Lakes."
Enbridge pushed back. Spokesman Ryan Duffy said the company is "disappointed for another delay in a project that has been under review for nearly a decade" and maintained the tunnel would "enhance environmental protection of the Great Lakes while maintaining critical energy reliability for the region." Enbridge said it is reviewing its legal options.
The court ruling lands in the middle of a broader political fight over the pipeline's future. Michigan Gov. Gretchen Whitmer has wanted to move Line 5 away from the waterway entirely. She and other state officials have been pursuing court cases since 2020 aimed at shutting down the pipeline under the straits, a campaign that has produced years of litigation but no final resolution.
Whitmer's position reflects a pattern among Democratic governors who have used regulatory and legal channels to block or delay energy infrastructure projects, often citing environmental concerns that conveniently align with progressive political priorities. The result is the same every time: projects stall, costs rise, and the energy reliability that families and businesses depend on gets treated as an afterthought. It is worth noting that Democratic leaders nationally have struggled to hold their coalition together on questions of energy policy and economic pragmatism.
The tunnel project itself was supposed to be the compromise, a way to keep oil moving while addressing environmental risk. Enbridge invested years and significant resources into the proposal. Now the Michigan Supreme Court has told regulators their homework was incomplete, and the pipeline's opponents are treating the ruling as proof the project should never have been approved at all.
Courts have played an increasingly aggressive role in shaping energy and infrastructure policy nationwide. The U.S. Supreme Court has also been active on questions of how far judicial power extends into political decisions. In a recent 5-4 ruling covered by National Review, the high court reversed a lower court order requiring Michigan to redraw dozens of congressional and legislative districts, reinforcing limits on federal judicial involvement in inherently political matters. The Michigan pipeline case sits on the other side of that coin, here, a state court stepped in to second-guess a state agency's technical judgment on an energy permit.
Strip away the politics, and the court's reasoning boils down to something conservatives should find familiar: a government agency cut corners. The Michigan Public Service Commission did not do the analysis its own rules required. It did not consistently compare alternatives. It did not weigh the public trust implications of a major construction project in one of the most ecologically significant waterways in North America.
That kind of regulatory sloppiness is not a victory for anyone. Pipeline supporters lose because the project gets delayed further, Enbridge has now spent the better part of a decade trying to get a tunnel built. Pipeline opponents lose because the underlying question of whether the aging pipeline should keep operating remains unresolved. And Michigan residents lose because their energy infrastructure sits in limbo while lawyers and regulators argue over process.
The broader trend is unmistakable. Whether the issue is ballots left uncounted in locked drop boxes or pipeline permits approved without proper analysis, government agencies keep failing at the basic task of following their own procedures. The public pays the price every time.
Meanwhile, the political dynamics around energy policy continue to fracture. Internal fights within the Democratic Party over economic and energy priorities have made it harder for leaders like Whitmer to chart a clear course. She wants the pipeline gone, but the court did not rule the pipeline must go, it ruled the commission must do its job properly before deciding whether the tunnel can proceed.
The Michigan Public Service Commission now faces a choice: conduct the thorough review the court demanded, or watch the tunnel proposal die a slow bureaucratic death. Enbridge says it is reviewing legal options, which could mean an appeal, a new permit application, or both. The tribal nations and environmental groups will almost certainly oppose any renewed effort.
The 73-year-old pipeline, meanwhile, keeps pumping more than half a million barrels of oil a day through the straits, the very arrangement everyone agrees carries risk. The tunnel was designed to reduce that risk. Now it sits in legal purgatory, alongside the separate court battles Whitmer launched in 2020 to shut the pipeline down entirely.
None of this serves the people of Michigan. Families who heat their homes with energy that flows through Line 5 did not ask for a decade of regulatory dysfunction. Neither did the tribal communities whose sacred waters sit at the center of the dispute. Both deserve a government that can make a decision and defend it, not one that approves permits it cannot justify and then watches courts clean up the mess.
Accountability in government starts with doing the work right the first time. The Michigan Public Service Commission failed that test, and now everyone, pipeline supporters, opponents, and the taxpayers stuck in between, gets to wait even longer for an answer.
