Line 5 Tunnel Clears Federal Hurdle, But Legal Fight Looms

The U.S. Army Corps of Engineers has issued the federal permit needed for Enbridge's proposed Great Lakes tunnel project, a major milestone for the plan to relocate the Line 5 pipeline beneath the Straits of Mackinac. The decision hands the Canadian energy giant a key regulatory victory after years of review, but it hardly closes the book on one of Michigan's most contentious infrastructure battles.

The tunnel, which would encase a replacement segment of the 71-year-old dual pipeline in a concrete-lined bore deep below the lakebed, is designed to eliminate the risk of an anchor strike in the open water. State regulators and the governor's office have long pressed for the project as the safest path forward, arguing that keeping the line in service is essential to regional propane and jet fuel supplies. Yet the Corps' approval does not resolve the separate state easement dispute, nor does it quiet the legal challenges that have shadowed the project since its inception.

Opposition Digs In

Environmental groups and several tribal nations have vowed to continue fighting the permit, pointing to the risk of a catastrophic spill and questioning whether the tunnel's safety claims hold up under scrutiny. Their concerns are not merely rhetorical; the Straits are a sensitive ecological corridor, and the Mackinac Band of Chippewa and Ottawas Indians have asserted treaty rights that they argue the project would violate. With the federal permit in hand, Enbridge now faces the harder task of defending it in court while navigating a shifting political landscape in Lansing.

For Michigan residents, the approval is less a conclusion than a pivot. The pipeline's fate will now hinge on a tangle of pending litigation, state-level permitting, and the durability of public opinion. Supporters see the tunnel as a pragmatic compromise that protects the water while preserving energy security; critics see a decades-long commitment to fossil fuel infrastructure that Michigan can ill afford. Either way, the Corps' green light ensures the debate over Line 5 will remain a defining political fault line in the state for years to come.