The U.S. Supreme Court has unanimously decided that Michigan's dispute over the Line 5 oil pipeline belongs in state court, advancing the state's long effort to potentially shut it down. The ruling clears the path for judges to assess risks from the pipeline's crossing of the Straits of Mackinac. Attorney General Dana Nessel hailed the decision as a victory against the threat of a catastrophic spill.
Justice Sonia Sotomayor wrote for the unanimous court that Enbridge Energy waited too long to seek federal jurisdiction, dismissing the company's arguments. The Canadian-owned pipeline spans 645 miles from Superior, Wisconsin, to Sarnia, Ontario, including a 4.5-mile segment along the lakebed of the Straits of Mackinac, which connect Lakes Michigan and Huron. Nessel has sought to revoke the easement since 2019, citing spill risks to the Great Lakes. “For far too long, following years of Enbridge’s delay tactics, the fear of a catastrophic spill from Line 5 has haunted our state,” she said in a statement. Enbridge argued for federal court due to safety laws and international ties, noting Canada's reliance on the line for half its oil supply to Ontario and Quebec. Michigan countered that it concerns state resource management. Legal experts view the ruling as significant. Andy Buschbaum of the Great Lakes Business Network called it a “big deal,” allowing state courts to decide if the pipeline should remain under the Great Lakes or pursue alternatives. All 12 Michigan tribes support shutdown, citing threats to waters and treaty rights. Whitney Gravelle, president of the Bay Mills Indian Community, said it creates space to uplift tribal voices. The case awaits resolution of a related federal appeal: Enbridge sued Governor Gretchen Whitmer in 2021 over her shutdown attempt, with the Sixth Circuit ruling for the company last November. Enbridge spokesperson Ryan Duffy emphasized federal safety findings of no issues warranting closure. Meanwhile, Enbridge seeks permits for a replacement tunnel, with decisions pending this summer.
