Army Corps OKs Line 5 Tunnel: A New Chapter in the Straits Saga

The U.S. Army Corps of Engineers has issued its permit for Enbridge's Line 5 tunnel beneath the Straits of Mackinac, a decision that reshapes one of Michigan's most enduring infrastructure and environmental disputes. The approval clears a major federal hurdle for the project, which would encase the aging dual pipelines in a deep underground tunnel drilled through bedrock, replacing the exposed lines that have long drawn scrutiny from tribal nations, environmental advocates, and state regulators.

For supporters, the tunnel represents a pragmatic middle path: it keeps the energy flowing to Michigan's Upper Peninsula and beyond while dramatically reducing the risk of a catastrophic spill in the open waters of the Great Lakes. Enbridge has argued that the tunnel is the safest possible configuration, and the Corps' environmental review appears to have accepted that framing, concluding that the buried route poses acceptable risks when weighed against the region's energy needs.

Victory in Washington, But the Fight Moves Home

Yet the federal green light does not end the controversy. The project still faces state-level permitting, ongoing litigation, and the unresolved question of an easement that the state of Michigan has sought to revoke. Governor Gretchen Whitmer's administration has remained publicly opposed to the tunnel, and legal challenges from environmental groups are expected to continue, arguing that the Corps' review failed to fully account for climate impacts and the risk of spills during construction.

There is also a deeper political undercurrent. The tunnel has become a proxy battle over Michigan's energy future, pitting those who see the pipeline as a necessary bridge against those who view any continued fossil fuel infrastructure as a step backward. The Corps' decision may settle the federal permitting question, but it does little to resolve the broader public debate over whether the Straits should remain a corridor for oil at all.

What happens next will unfold in courtrooms and hearing rooms across the state. The tunnel's fate now hinges on state permits, legal rulings, and the shifting winds of Michigan politics. For residents who have watched this saga for years, the Corps' approval is a significant milestone, but it is far from the final word.