Michigan Secures State Court Hearing for Line 5 Pipeline Closure Battle

Michigan’s decades-long effort to shut down the Line 5 pipeline will proceed in state court after the U.S. Supreme Court unanimously ruled that the dispute belongs there. The decision clears the path for judges to determine whether the aging oil pipeline can continue crossing the Straits of Mackinac, a critical waterway connecting Lakes Michigan and Huron.

The ruling is widely viewed as a win for tribes, environmental advocates, and Michigan Attorney General Dana Nessel, who has sought to revoke the easement allowing the pipeline to cross the Straits since 2019. Nessel has cited the risk of a catastrophic oil spill as justification for the shutdown.

“For far too long, following years of Enbridge’s delay tactics, the fear of a catastrophic spill from Line 5 has haunted our state, threatening to turn our most vital natural resource into a man-made disaster.”

Line 5, owned by the Canadian company Enbridge Energy, transports crude oil and natural gas liquids across a 645-mile route from Superior, Wisconsin, to Sarnia, Ontario. A critical 4.5-mile segment of the pipeline runs along the lakebed of the Straits of Mackinac.

In the unanimous decision, Justice Sonia Sotomayor wrote that Enbridge waited too long to move the case to federal court and that the company’s arguments were unpersuasive. Legal experts emphasized the significance of the procedural ruling, as it determines which court will ultimately decide the pipeline’s future.

Enbridge’s legal team had argued that a federal court was the proper venue due to the involvement of federal safety laws and international agreements. (The Canadian government has opposed shutting down Line 5, which supplies half of the oil needs for Ontario and Quebec.) Michigan countered that the pipeline violates the state’s authority to manage its natural resources, making this a matter for state court.

With the jurisdiction question resolved, legal experts say state courts can now proceed to decide whether the portion of the pipeline spanning the Straits should be shut down. Andy Buschbaum, a lawyer for the Great Lakes Business Network—which filed supporting briefs—called the unanimous decision a “big deal.”

“The justices of the court, regardless of ideology, agreed that it’s the state court that’s the proper court to hear this dispute. We’re finally in a position for the state court to actually decide whether Line 5 belongs on the bottom of the Great Lakes, or whether there are alternatives.”

The case’s shift to Michigan’s 30th Circuit Court is also expected to bring tribal sovereignty into sharper focus. All 12 federally recognized tribes in Michigan have demanded the shutdown of Line 5, citing threats to their waters, treaty rights, and cultural practices. Though not part of the Supreme Court proceedings, tribal leaders anticipate greater influence in the state court battle.

“It will really create space now for tribes to uplift their voices in the proceedings, to uplift tribal treaty rights, to uplift the protection of natural resources and ultimately the preservation of our cultural lifeways.”