The attorneys general (AG) of Minnesota, California and Wisconsin have formally lent their support to a lawsuit filed by Michigan AG Dana Nessel seeking to shut down Enbridge Inc.’s Line 5 light crude oil and natural gas liquids (NGL) pipeline across Michigan’s Straits of Mackinac.

AGs Xavier Becerra of California, Keith Ellison of Minnesota and Joshua Kaul of Wisconsin filed an amicus brief last week in the 30th Judicial Circuit Court of Michigan in Ingham County arguing in favor of the complaint filed in late June. Nessel is seeking to invalidate an easement that allows Line 5, which was built in 1953 and moves up to 540,000 b/d of crude and NGLs, to operate.

To support Nessel’s case, the amicus brief cited the public trust doctrine, a legal principle which holds that “states…hold important natural resources such as tidelands, submerged lands and the beds of inland navigable waters in trust for the benefit of the public,” and states have the authority “to reject uses of these lands previously allowed by a state.”

The brief implores the court to reject Enbridge’s contention that Line 5’s operation is protected under the federal Pipeline Safety Act, arguing that, “Michigan is free to exercise its public trust powers to determine whether pipelines may cross its sovereign lands and, if so, where that may occur. That is qualitatively different from regulating how a pipeline operator must design, construct, maintain, test, and operate the pipeline.”

Separately, the Bad River Band of the Lake Superior Tribe of Chippewa Indians is seeking a court order prohibiting Enbridge from using Line 5 to transport oil and NGLs across the reservation. It also wants the pipeline removed from the reservation.

The Bad River Band is also alleging “unsafe conditions at a specific location of the pipeline on the reservation and requesting a declaration by the court that the Band has regulatory authority over Line 5,” Enbridge said in its third quarter results. A trial date to resolve the complaint has been set for July 2021.

Under an agreement with the Mackinac Straits Corridor Authority, Enbridge is seeking to replace Line 5 with a new pipeline that would be enclosed within a concrete-reinforced tunnel underneath the straits. Enbridge has said the tunnel design would remove the threat of anchor strikes, a constant concern for the current Line 5 pipeline, which passes above the lakebed.

In March, Nessel’s office issued an opinion declaring that the December 2018 law creating the Corridor Authority and paving the way for the Line 5 replacement was unconstitutional.

Gov. Gretchen Whitmer subsequently halted work on the project. In a victory for Enbridge in late October, the Michigan Court of Claims ruled that the law creating the Corridor Commission was constitutional, a decision that Nessel’s office has appealed.

In the third quarter conference call, Enbridge’s Guy Jarvis, president of liquids pipelines, said the company was encouraged by “the decision from the courts around the tunnel agreements” and expects “to be in a position probably in the first quarter of next year to start making the necessary applications to pursue the completion of the tunnel, and that’s exactly the path that we’re on.”

Regarding the dispute with the Bad River community, Jarvis said, “we are not in a position to suggest that we’ve got a deal in any way, shape or form just yet, but certainly, a lot more broad engagement.”