The U.S. Supreme Court unanimously ruled Michigan’s Line 5 dispute belongs in state court, setting the stage for judges to weigh whether the pipeline can keep crossing the Straits of Mackinac.
Michigan’s long-running fight over the Line 5 pipeline is heading back to state court after the U.S. Supreme Court unanimously ruled that the dispute must be heard there—an outcome closely watched by tribes, environmental groups, and the state attorney general.
The decision clears a key procedural hurdle for Michigan. where Attorney General Dana Nessel has argued since 2019 that the state should revoke the easement that allows Enbridge’s pipeline to cross the Straits of Mackinac.. The Straits connect Lake Michigan and Lake Huron. and the state’s central concern is spill risk from aging infrastructure running along a sensitive waterway.
Line 5 carries crude oil and natural gas liquids across a 645-mile route from Superior, Wisconsin, to Sarnia, Ontario.. A critical 4.5-mile segment lies beneath the lakebed of the Straits, making the stakes more than legal.. For Michigan. the pipeline sits at the intersection of public safety. environmental protection. and the long-term health of the Great Lakes—resources that underpin tourism. fishing. and drinking-water systems for millions of people.
The Supreme Court’s ruling turned on where the case should be decided. not immediately on whether Line 5 should be shut down.. Writing for the unanimous court. Justice Sonia Sotomayor said Enbridge waited too long to shift the dispute to federal court. and that the company’s arguments were not persuasive.. Enbridge had contended that federal safety laws and international agreements should place the matter in a federal forum.
Legal experts described the jurisdiction ruling as significant because it determines the decision-making path for the pipeline’s future.. With the question of venue settled. Michigan’s state courts can now address the substance: whether that lakebed portion should continue operating. and whether alternatives could satisfy safety and operational needs.. The procedural win was also framed as a moment of momentum for Michigan’s broader strategy to force the pipeline’s removal.
For tribes. the ruling carries additional weight because it creates more room—within Michigan’s legal process—for treaty rights and sovereignty-based arguments to shape the case’s trajectory.. All 12 federally recognized tribes in Michigan have called for Line 5 to be shut down. arguing it threatens their waters. treaty rights. and ways of life.. While the tribes were not part of the Supreme Court proceedings. Michigan’s state court fight is expected to sharpen the focus on how those concerns should be evaluated.
One of the most consequential parts of Line 5’s timeline is what happens next procedurally.. The case is not expected to be heard in Michigan’s 30th Circuit Court until an appeal of a separate case moves through federal court—meaning the legal calendar will continue to stretch.. In another dispute, Enbridge sued Governor Gretchen Whitmer in 2021, arguing the state lacks authority over pipeline safety.. The Sixth Circuit sided with Enbridge in November, and Whitmer appealed that decision in January.
Meanwhile, Enbridge has continued defending its plans on the merits as well as on the procedural front.. The company has pointed to a federal assessment and has argued there are no safety issues that would justify shutting down Line 5.. Enbridge spokesperson Ryan Duffy also referenced a position taken by federal regulators that the matter should not be treated as an emergency requiring cessation.
That argument is unfolding alongside engineering and regulatory developments. including Enbridge’s proposal to replace the dual pipelines beneath the Straits with a tunnel solution that would house a segment buried under the lakebed.. The company is awaiting state and federal permits, with decisions expected this summer.. In parallel. other court battles continue: Michigan’s Public Service Commission issued a 2023 permit. and the Michigan Supreme Court recently heard oral arguments from tribes and environmental groups seeking to overturn it.. In Wisconsin. the Bad River Band of Lake Superior Chippewa has also pursued litigation aimed at stopping construction tied to Line 5 infrastructure near tribal watershed areas.
From an environmental-policy perspective, the Supreme Court’s venue decision narrows the uncertainty that often surrounds complex infrastructure disputes.. When jurisdiction is unresolved. parties can spend years litigating procedural angles rather than tackling the harder questions—what level of risk is acceptable. what protections are realistic. and what happens if conditions change over decades.. By pushing the case into state court. the ruling sets up a forum that Michigan and its allies believe is better aligned with state authority over natural resources and with the principle that Great Lakes protections must be treated as more than an abstract regulatory question.
For ordinary residents, the courtroom outcome is not just legal theater.. A pipeline under the Straits sits close to ecosystems that support fisheries and recreation. and to the broader water infrastructure on which communities rely.. A spill—whether small. slow. or catastrophic—can impose costs that last far beyond any single incident: cleanup burdens. ecosystem recovery. and long-term impacts on public trust.
As Michigan’s case moves forward. the focus will likely shift from whether the dispute belongs in a particular court to how the merits should be weighed—especially regarding safety. environmental risk. and the role of tribal treaty rights.. For those pushing for shutdown. the moral dimension has become unavoidable; for Enbridge. the company argues its upgrades and permitting path are designed to be safer than the status quo.. Whatever the eventual outcome. Misryoum’s sense is that the ruling marks a turning point in how the Line 5 controversy is likely to be decided: not just by federal or state regulations. but by the legal system Michigan has been trying to activate for years.