In a landmark decision, the US Supreme Court has sided with Michigan in a prolonged legal battle to halt operations of a critical section of the ageing Line 5 pipeline, which runs beneath the Straits of Mackinac connecting Lake Michigan and Lake Huron. The unanimous ruling, delivered on April 22, 2026, maintains that the state’s lawsuit will remain in state court, effectively thwarting Enbridge’s attempts to transfer the case to a federal jurisdiction.
Legal Tug-of-War over Line 5
The Supreme Court’s decision comes amid a tumultuous legal backdrop surrounding Line 5, a pipeline that has transported crude oil and natural gas liquids since 1953. Michigan Attorney General Dana Nessel initiated the lawsuit in June 2019, seeking to nullify the easement allowing Enbridge to operate the 4.5-mile section of the pipeline that lies beneath the Great Lakes. This legal action was spurred by mounting safety concerns, particularly following revelations that significant gaps in the pipeline’s protective coating had been acknowledged by Enbridge engineers as early as 2014.
In June 2020, Nessel secured a restraining order from Ingham County Judge James Jamo, which temporarily halted the pipeline’s operations. However, Enbridge subsequently resumed activities after meeting certain safety criteria, igniting further controversy.
Enbridge’s Attempt to Shift Jurisdiction
Enbridge sought to shift the lawsuit to federal court in 2021, arguing that the case had implications for US-Canada trade. Nevertheless, a three-judge panel from the Sixth US Circuit Court of Appeals ruled in June 2024 that the company had failed to adhere to a 30-day deadline for such a move, thus returning the case to Judge Jamo in state court. Justice Sonia Sotomayor’s opinion underscored the court’s stance that Enbridge’s delay precluded their request.
The situation worsened when the Michigan Department of Natural Resources, under Governor Gretchen Whitmer, revoked the easement for Line 5 in 2020. Enbridge launched a federal lawsuit contesting this revocation, which a federal judge temporarily upheld but is currently under appeal. Whitmer’s administration has faced setbacks, including a Supreme Court decision that barred her from being sued in federal court concerning the matter.
Environmental Concerns and Community Opposition
The concerns surrounding Line 5 are not merely legal but deeply rooted in environmental advocacy. Activists and local communities have long warned that a ruptured pipeline could lead to catastrophic spills, threatening the delicate ecosystem of the Great Lakes. The advocacy intensified after an anchor struck the pipeline in 2018, raising alarms about its structural integrity.
In response to the growing environmental risks, Enbridge is now seeking to encase the pipeline in a protective tunnel beneath the Straits. While the Michigan Public Service Commission granted the necessary permits in 2023, this decision has been met with fierce opposition from environmental groups and local tribes, who have filed a lawsuit aiming to invalidate these permits. The state Supreme Court is currently deliberating on this critical case, which could have significant implications for the future of the pipeline.
Wider Implications and Ongoing Legal Challenges
The legal battles surrounding Line 5 are not confined to Michigan. In Wisconsin, a federal judge has mandated that Enbridge must cease operations on a segment of Line 5 traversing the Bad River Band of Lake Superior’s reservation. The company is appealing this ruling while simultaneously working to reroute the pipeline around the reservation. However, this rerouting has drawn criticism from the Bad River Band and environmental advocates, who argue that the construction will result in severe ecological damage.
As these multiple legal disputes unfold, the fate of Line 5 remains precarious, with potential ramifications for both regional ecosystems and energy policy across the US and Canada.
Why it Matters
The Supreme Court’s ruling is a pivotal moment in the ongoing struggle for environmental justice in the Great Lakes region. It highlights the critical intersection of legal frameworks and ecological preservation, as communities and their advocates strive to protect vital natural resources from the threats posed by fossil fuel infrastructure. The outcome of these legal battles will not only affect the future of Line 5 but could also set significant precedents for environmental law and energy policy in the United States. The stakes are high, not just for Michigan but for the broader fight against climate change and the preservation of our planet’s most precious waterways.
