A Michigan circuit court judge has ruled that the state’s long-running lawsuit against Enbridge over the Line 5 pipeline can move forward, despite a related case pending before the U.S. Supreme Court.
On Monday, Judge James Jamo denied the Canadian pipeline operator’s request to stay the case in Ingham County Circuit Court. Enbridge had argued the state proceedings should be put on hold until the nation’s highest court decides whether certain aspects of the dispute fall under federal jurisdiction.
Attorney General Dana Nessel welcomed the decision, saying Line 5 — twin pipelines that have run along the bottom of the Straits of Mackinac since 1953 — pose too great a risk to the Great Lakes. Her office argues that the 72-year-old lines are vulnerable to anchor strikes, corrosion, or other failures that could lead to an environmental catastrophe in one of the most ecologically sensitive waterways in North America.
Enbridge, for its part, maintains that only the federal Pipeline and Hazardous Materials Safety Administration (PHMSA) has authority to determine whether Line 5 is safe. The company also points to its plan to replace the underwater stretch of pipeline with a new concrete tunnel bored beneath the lakebed — a project still undergoing state and federal permitting.
In a statement after the ruling, Enbridge warned that efforts to shut down the existing line could threaten energy security not just in Michigan but across the region. Line 5 carries up to 540,000 barrels of crude oil and natural gas liquids per day, serving refineries in Michigan, Ohio, Pennsylvania, Ontario, and Quebec. Shutting it down, the company says, would disrupt fuel supplies and raise prices for consumers.
The state’s lawsuit, filed six years ago, has faced repeated delays as Enbridge pursued legal motions and appeals. Judge Jamo’s order makes clear that the case can proceed in tandem with the federal proceedings, potentially setting up parallel tracks of litigation.
A shorter version of this story first appeared on WVBI.net. This version was created with AI assistance using reporting from Interlochen Public Radio and other sources.
📅 Timeline: Michigan’s Legal Fight Over Line 5
1953 — Enbridge’s twin Line 5 pipelines begin operating along the bottom of the Straits of Mackinac, connecting Lake Michigan and Lake Huron.
2010 — Enbridge’s Line 6B ruptures near Marshall, Michigan, spilling more than 840,000 gallons of oil into the Kalamazoo River. The disaster heightens scrutiny of the company’s pipelines across the Great Lakes region.
2018 — Then-Governor Rick Snyder strikes a deal with Enbridge to build a tunnel beneath the Straits to house a replacement segment of Line 5.
2019 — Michigan Attorney General Dana Nessel files a lawsuit in Ingham County Circuit Court, arguing Line 5 is a public nuisance and should be shut down to protect the Great Lakes.
2020–2022 — Enbridge counters with multiple legal motions and argues that federal regulators, not Michigan courts, have jurisdiction. Parallel cases begin moving through both state and federal courts.
2021 — Governor Gretchen Whitmer orders Enbridge to stop operating Line 5 in the Straits. Enbridge refuses, citing federal jurisdiction and Canada’s invocation of a 1977 treaty with the U.S. guaranteeing cross-border energy flows.
2023 — The Michigan Public Service Commission grants Enbridge a key permit for its proposed tunnel project, though federal permits remain pending.
2024 — The U.S. Supreme Court agrees to review part of the jurisdictional dispute, but has not yet issued a decision.
August 2025 — Circuit Court Judge James Jamo denies Enbridge’s request to pause Michigan’s case, allowing the state lawsuit to proceed even while the Supreme Court case remains pending.
