Overview
- Justices heard two appeals asking to remand the Michigan Public Service Commission’s 2023 approval for fuller review under the Michigan Environmental Protection Act and the public trust doctrine.
- Tribal nations and environmental groups argued the commission excluded evidence, failed to assess reasonable alternatives or public need, and overlooked treaty‑protected fishing and cultural resources in the Straits.
- Enbridge urged the court to uphold the permit, calling the tunnel the safest option to reduce spill risk and citing confidence in the commission’s record and process.
- Questions from the bench, including from Justice Elizabeth Welch, tested how a ruling might apply beyond Line 5, potentially triggering broader reviews for pipeline replacements or other utility upgrades.
- Parallel proceedings continue, including a federal district‑court order limiting Michigan’s easement enforcement efforts and a recent U.S. Army Corps final environmental impact statement that will inform a federal Record of Decision.