Enbridge Energy’s Line 5 pipeline, seen here, has long been a source of controversy in Michigan because of fears an underwater section could rupture and cause an oil spill in the Straits of Mackinac. (Courtesy of the Michigan Department of Environment, Great Lakes and Energy via the Associated Press)

(This story was originally published by Bridge Michigan, a nonprofit and nonpartisan news organization. Visit the newsroom online: bridgemi.com.)

In a packed courtroom in Lansing, lawyers for Enbridge Energy and its critics debated before Michigan’s highest court Wednesday about whether the state acted properly in issuing a key permit for Enbridge’s proposed Line 5 tunnel.

David Scott, a lawyer for a coalition of Michigan tribes, argued state energy regulators issued the tunnel permit based on “a lopsided analysis that needs to be corrected.” He asked the court to order a more thorough review of the plan to encase a portion of the petroleum pipeline, which currently rests in the open water of the Great Lakes, into a tunnel buried beneath the Straits of Mackinac.

Enbridge lawyer John Bursch, meanwhile, argued state regulators correctly concluded the tunnel is the safest option for a pipeline that will keep operating one way or another.

“Where do you want the pipeline?” Bursch asked. “Do you want it in the tunnel or do you want it operating in the water?”

The case stems from the Michigan Public Service Commission’s December 2023 approval of Enbridge’s proposal to reroute a 4-mile segment of the controversial petroleum pipeline out of the open water and into the tunnel.

That decision prompted outcry from pipeline opponents, who have argued the 72-year-old pipeline should be shut down rather than merely rerouted. A coalition of four Michigan tribal nations and a Traverse City-based environmental group responded with two separate lawsuits, triggering a legal dispute that reached Michigan’s highest court after the Michigan Court of Appeals sided with the state.

The tribes — the Bay Mills Indian Community, Grand Traverse Band of Ottawa and Chippewa Indians, Little Traverse Bay Band of Odawa Indians and Nottawaseppi Huron Band of the Potawatomi, joined by the Environmental Law and Policy Center and the Michigan Climate Action Network — argue the commission should have considered possible environmental impacts such as oil spill risks along the length of the 645-mile pipeline.

Traverse City-based Flow Water Advocates, meanwhile, argues the commission inadequately considered the tunnel project’s impact on the Great Lakes as a public trust resource. Michigan’s public trust doctrine says the state holds resources like the Great Lakes and bottomlands in trust for the people.

Bursch’s argument that the pipeline will run one way or another rested on the assumption Enbridge will win a separate legal dispute with state officials who have ordered the pipeline shut down for fear it could rupture and cause a catastrophic Great Lakes oil spill.

But some justices appeared skeptical.

“Is there a final determination on that point yet?” Chief Justice Megan Cavanagh asked Bursch.

The answer is not yet. While U.S. District Court Judge Robert Jonker ruled in December that federal pipeline safety law leaves Michigan no authority to order a shutdown, the state is appealing the decision.

The Michigan Supreme Court case argued Wednesday is one of several ongoing regulatory and judicial deliberations that could seal the fate of the controversial pipeline.

Calgary, Alberta-based Enbridge has been using Line 5 to transport crude oil and natural gas liquids between Superior, Wisconsin, and Sarnia, Ontario, since 1953. The line routes through the Upper Peninsula, including Dickinson and Iron counties.

In addition to the federal appeals case, Enbridge and Michigan are awaiting a key U.S. Supreme Court decision tied to Michigan Attorney General Dana Nessel’s attempt to shut down the pipeline. Meanwhile, the state and federal government are considering whether to issue other permits for the tunnel project.

On Wednesday, Michigan justices peppered both Enbridge and its opponents with questions, giving no indication of how they might rule in the state permitting dispute.

When Scott argued that Enbridge’s request to reroute Line 5 should have triggered a broad state review of the entire pipeline’s environmental impacts, Justice Elizabeth Welch expressed concern about setting a precedent for prolonged reviews of other, more routine utility reroutes.

“Where do we draw the line?” she asked.

When Enbridge lawyer Bursch began to warn about the potential economic implications of shutting down the pipeline, Justice Richard Bernstein interjected, “What would you say are the real-life implications if there were a spill?”

Lawyers for both sides accused their opponents of using the courts to needlessly delay the final outcome of a now decade-long dispute over the fate of Line 5.

Amid mounting calls to shut down the lakebottom pipeline lest it cause an oil spill in the Straits, Enbridge reached a deal in 2018 with the administration of then-Gov. Rick Snyder to build the tunnel project, estimating at the time the project would cost $500 million and be complete in 2024.

But groundbreaking has yet to begin as Enbridge awaits multiple permitting decisions and navigates legal disputes with those who favor a shutdown.

At the end of Wednesday’s nearly two-hour proceedings, justices gave no indication of their timeline for making a decision in the case. The court’s current term ends July 31.