Michigan Line 5 Tunnel Debate: Federal Permit, State Review, and the Public Trust Doctrine in Water policy

Episode overview

Science Friday examines the Line 5 oil and gas liquids pipeline through Michigan’s Straits of Mackinac, the proposed tunnel, and the broader push to shut down Line 5 amid environmental worries about the Great Lakes. Federal and state actions collide with Indigenous treaty rights and public-ownership ideas about water resources.

• Key developments include a U.S. Army Corps of Engineers permit for a tunnel and a Michigan Supreme Court ruling voiding a state permit, signaling a stalled project at the state level.
• Vivian Law discusses coalitions on both sides, including environmental groups, tribes, Enbridge, labor, and government actors.
• Oday Saleem explains the public trust doctrine as a centuries-old principle that water and public resources should be managed for present and future generations, and how it is being invoked in climate and environmental litigation.
• The conversation highlights how public trust analysis may influence future permitting decisions around Great Lakes water resources.

Introduction and context

The Science Friday episode centers on the controversial Line 5 pipeline that transports crude oil and natural gas liquids from Wisconsin to Ontario via the Straits of Mackinac. Built in the 1950s, the dual pipelines at the lake bottom are opposed by environmental groups, Indigenous tribes, and Great Lakes activists who fear spills could devastate one of the world's largest freshwater ecosystems. After years of court battles and regulatory scrutiny, the episode tracks two parallel strands: the tunnel project intended to reroute the pipeline through a submerged tunnel beneath the lake bed, and the broader effort to shut down Line 5 altogether, framed by the transition to cleaner energy sources.

The players and the latest turn of events

In the latest developments, federal authorities approved Enbridge's tunnel plan, with the U.S. Army Corps of Engineers issuing a permit for the tunnel project. This decision drew sharp condemnation from Michigan tribes who argued the permit ignored treaty rights and was issued without adequate tribal consultation. Separately, a Michigan Supreme Court decision vacated a state environmental permit, requiring a fuller environmental harm assessment and the possibility of new testimony and hearings, pushing the timeline into the next year. Despite federal approval, the tunnel remains stalled at the state level, highlighting the clash between federal authorization and state regulatory processes in environmental governance.

Coalitions and arguments on both sides

The episode outlines the opposing coalitions: environmental groups and tribes emphasize risks to water, environment, and tribal resources; Enbridge, along with labor unions and parts of the energy industry, argues the tunnel would create a safer, more secure pipeline and support energy infrastructure in the Midwest. The discussion also touches on broader geopolitical dynamics, including Canadian government involvement and support from other states, as stakeholders weigh energy reliability against environmental protection and Indigenous rights.

The public trust doctrine explained

The second guest, Oday Saleem of the University of Michigan Law School, offers a legal lens on the public trust doctrine. He traces the doctrine from ancient concepts of shared resources to a mature state law principle, where the state is a trustee of water bodies and shoreline resources to safeguard public uses such as navigation, fishing, recreation, and ecosystem health. In Line 5, decades-old easements granted for pipeline construction on the lakebed are reexamined under this doctrine, which now requires the state to ensure that authorized activities do not harm the public trust values and may require public analyses of potential harm and improvements.

Broader implications and reflections