In a unanimous decision, the U.S. Supreme Court has ruled in favor of Michigan, allowing the state's lawsuit against Enbridge Energy to proceed in state court rather than being transferred to federal jurisdiction. The ruling, issued on Wednesday, centers on a decades-old pipeline known as Line 5 that runs beneath the Straits of Mackinac, connecting Lake Michigan and Lake Huron. Justice Sonia Sotomayor authored the opinion, stating that Enbridge waited too long to attempt moving the case to federal court.
The dispute revolves around a 4.5-mile section of the pipeline, which has transported crude oil and natural gas liquids from Superior, Wisconsin, to Sarnia, Ontario, since 1953. Michigan Attorney General Dana Nessel, a Democrat, filed the lawsuit in state court in June 2019, seeking to void the easement that permits Enbridge to operate this underwater segment. According to court records, Nessel's action was driven by mounting concerns over the pipeline's safety and the risk of an environmental disaster in the Great Lakes.
In June 2020, Ingham County Judge James Jamo granted a restraining order in Nessel's favor, effectively shutting down the pipeline operations. However, Enbridge was permitted to resume activities after complying with additional safety requirements imposed by the court. Enbridge, a Canadian energy company, argued in 2021 that the case should be heard in federal court because it involves international trade between the U.S. and Canada. The company moved the lawsuit accordingly, but a three-judge panel from the 6th U.S. Circuit Court of Appeals ruled in June 2024 that Enbridge had missed the mandatory 30-day deadline for such a jurisdictional shift, sending the matter back to Judge Jamo.
The Supreme Court's decision upholds that appeals court ruling, emphasizing procedural timelines in federal removal statutes. "The Enbridge energy company waited too long to try to move the case to federal court," Justice Sotomayor wrote for the court, as reported by the Associated Press. This unanimous verdict, without any dissenting opinions, underscores the high court's focus on strict adherence to filing deadlines in complex interstate and international disputes.
Line 5 has been a flashpoint for environmental advocates and state officials for years, particularly since 2017 when Enbridge engineers disclosed that they had been aware of gaps in the pipeline's protective coating since 2014. These revelations heightened fears of a potential rupture in the Straits of Mackinac, a vital waterway linking two of the Great Lakes. The situation escalated in 2018 when a boat anchor struck the pipeline, causing damage and further intensifying public and official concerns about a possible catastrophic oil spill that could devastate the region's ecosystem and economy.
Under Democratic Governor Gretchen Whitmer, the Michigan Department of Natural Resources revoked the easement for the Straits section in 2020, citing safety risks. Enbridge responded by filing a separate federal lawsuit challenging this revocation, arguing that it interferes with critical energy infrastructure. Meanwhile, the company has pursued alternatives, including plans to encase the underwater pipeline in a protective tunnel. In 2023, the Michigan Public Service Commission approved the necessary state permits for this project, but Enbridge still requires federal approval from the U.S. Army Corps of Engineers and state clearance from the Michigan Department of Environment, Great Lakes and Energy.
The legal battles extend beyond Michigan's borders. In Wisconsin, a federal judge in Madison ordered last summer that Enbridge must shut down the portion of Line 5 crossing the Bad River Band of Lake Superior Chippewa's reservation within three years. This ruling stemmed from treaty rights and environmental protection claims by the tribe. Enbridge has proposed rerouting the pipeline to avoid the reservation and has appealed the decision to the 7th U.S. Circuit Court of Appeals, where the case remains pending.
Attorney General Nessel has long voiced strong opposition to the pipeline's continued operation under the straits. In statements following earlier court victories, she emphasized the potential for irreversible damage to the Great Lakes, which supply drinking water to millions across the Midwest. "This pipeline poses an unacceptable risk to our state's precious water resources," Nessel said in a 2020 press release after securing the restraining order, according to Michigan state records. Environmental groups, including those aligned with the Sierra Club and local advocacy organizations, have echoed these sentiments, highlighting the pipeline's age and vulnerability.
Enbridge, on the other hand, maintains that Line 5 is essential for regional energy security and economic stability. The company transports about 540,000 barrels of oil and natural gas liquids daily through the pipeline, supporting refineries and jobs in both the U.S. and Canada. In response to the Supreme Court's ruling, Enbridge spokesperson Michael Pranikoff stated, "We respect the court's decision and remain committed to safely operating Line 5 while pursuing all necessary approvals for our tunnel project." The company has invested millions in safety enhancements and monitoring since the coating issues were identified.
The Straits of Mackinac, a narrow channel just 4 miles wide at its narrowest point, carries heavy shipping traffic and supports a delicate aquatic environment teeming with fish species and serving as a migration route for birds. A spill from Line 5 could contaminate up to 20% of the world's fresh surface water, according to estimates from the National Wildlife Federation. Historical precedents, such as the 2010 Enbridge spill in Michigan's Kalamazoo River that released over a million gallons of oil, fuel the urgency of the current debate.
Governor Whitmer has positioned the Line 5 issue as a cornerstone of her administration's environmental agenda. In 2020, she declared an emergency over the pipeline, though that move was later challenged in court. Her administration's revocation of the easement was part of a broader effort to transition away from fossil fuel infrastructure toward cleaner energy sources. Critics, including some business groups and Republican lawmakers in Michigan, argue that shutting down Line 5 could lead to higher energy costs and supply disruptions, potentially affecting gas prices at the pump.
The Supreme Court's involvement in this case highlights the intersection of state sovereignty, federal jurisdiction, and international commerce in energy policy. Legal experts note that the ruling sets a precedent for how companies can invoke federal courts in disputes with environmental implications. "This decision reinforces the importance of timely action in removal petitions," said University of Michigan law professor Nicholas Bagley, who has followed the case closely. Bagley added that while the jurisdictional question is resolved, the underlying merits of Michigan's claims will now be tested in state court.
Looking ahead, the state court proceedings could determine the pipeline's fate in the Straits, potentially leading to a full shutdown if Nessel prevails. Enbridge's tunnel proposal, if approved, might offer a compromise by relocating the line out of the waterbed. However, federal and tribal challenges in Wisconsin add layers of uncertainty. The Bad River Band has expressed satisfaction with their federal court win but remains vigilant about enforcement, with tribal chairman Bryan Bainbridge stating, "Our lands and waters must be protected for future generations."
As the legal saga continues, stakeholders on all sides prepare for prolonged litigation. Michigan officials are optimistic about advancing their case in state court, while Enbridge focuses on regulatory hurdles for its mitigation plans. The outcome could influence similar disputes over aging infrastructure across the U.S., balancing environmental protection against energy needs. For now, Line 5 remains operational under strict oversight, a tenuous status amid the Great Lakes' pristine but vulnerable waters.
The broader implications extend to U.S.-Canada relations, given the pipeline's cross-border role. Diplomatic notes from the Canadian government have urged resolution without disruption, emphasizing mutual economic interests. In Michigan, public opinion polls show strong support for decommissioning the Straits section, with over 60% of residents favoring closure according to a 2023 survey by the Glengariff Group. Yet, the energy sector warns of ripple effects on supply chains if the pipeline is idled prematurely.