WASHINGTON, July 17 — The Line 5 tunnel project has secured its federal permit approvals, but the figure that matters for investors and policymakers is the stack of unresolved legal challenges that could stall construction for years. The bottom line: despite the green light on January 10, 2024, the project remains tangled in federal and state lawsuits, an incomplete state easement, and a separate federal permit review that has yet to conclude. The most significant legal threat comes from the Bay Mills Indian Community.
The Native American tribe filed a lawsuit in federal court arguing that the tunnel violates their treaty rights and the National Environmental Policy Act. That case directly challenges the legal foundation of the project, and a ruling against Enbridge could halt work regardless of other permits.
Federal courts have historically treated tribal treaty claims with serious scrutiny, making this a high-risk variable for the project timeline.
Environmental challenges in state court
The National Wildlife Federation and other environmental groups have taken a separate legal path, filing lawsuits in state court. Their argument: the Michigan Department of Environment, Great Lakes, and Energy — known as EGLE — failed to adequately consider environmental impacts under the Michigan Environmental Protection Act. State court rulings in Michigan have previously slowed or blocked major infrastructure projects when environmental review standards were found lacking, and this case follows that established pattern.
By the numbers, the project faces at least two active court cases, one incomplete state easement, and one pending federal permit review. That is four distinct hurdles, any one of which could prove decisive.
The missing easement
The project requires a final easement from the Michigan Department of Natural Resources. That easement has not yet been granted. Without it, Enbridge cannot proceed with construction on state-owned land, regardless of what federal or state courts decide.
The DNR has not publicly signaled a timeline for its decision, leaving the project in a holding pattern on that front. The U.S. Army Corps of Engineers is also reviewing a federal permit for the project.
That review process is separate from the permit approvals already granted in January 2024, and it adds another layer of federal regulatory uncertainty. Corps reviews can take months or years, particularly when challenged by environmental groups or tribal nations.
What to watch next
Investors will note that these legal battles could delay construction for years. The combination of tribal treaty claims, state environmental lawsuits, a missing state easement, and a pending federal permit creates a legal landscape where no single approval guarantees progress. The January 2024 permit approvals were necessary but far from sufficient.
The next major milestone to watch is the federal court ruling on the Bay Mills lawsuit. A decision against the tribe would remove one obstacle but leave the state lawsuits and the DNR easement unresolved.
A decision in favor of the tribe could effectively stop the project. Either way, the path forward runs through the courts and the Michigan state government, not just through federal permitting agencies.
