U.S. Supreme Court Denies Whitmer's Sovereign Immunity Claim, Enbridge Can Sue State Over Line 5 Pipeline

LANSING — The U.S. Supreme Court has rejected Michigan's appeal to use sovereign immunity in a lawsuit filed by Enbridge Energy, clearing the way for the Canadian oil company to proceed with its legal challenge against state efforts to shut down the controversial Line 5 pipeline in the Straits of Mackinac.

On Tuesday, the Supreme Court denied Michigan's petition for a writ of certiorari, meaning the justices will not review the state's appeal that argued Governor Gretchen Whitmer has sovereign immunity from the lawsuit. This decision leaves standing lower court rulings that allow Enbridge to sue Michigan for attempting to use its regulatory power to scuttle Line 5 and stop the company from building a tunnel under the straits.

"We are disappointed by the Supreme Court's decision not to review this important issue of state sovereignty," said Danny Wimmer, a spokesman for Attorney General Dana Nessel's office. "We will continue to fight for the people of Michigan on these vital issues concerning the Line 5 pipelines in the Straits."

Enbridge, for its part, said it agreed there was no need to review lower court rejections of Michigan's sovereign immunity plea. "The Sixth Circuit made clear that Enbridge's suit falls within the exception to sovereign immunity," said Ryan Duffy, a spokesman for Enbridge.

Lower Court Rulings Set the Stage

The U.S. Supreme Court's decision follows a series of lower court rulings that have consistently sided with Enbridge. A U.S. District Court in December ruled that federal law governing pipeline safety preempts the state's multi-year effort to shutter Line 5.

According to the Sixth Circuit Court of Appeals, Enbridge's lawsuit falls within an exception to sovereign immunity that allows a suit to continue if it alleges a violation of federal law or the U.S. Constitution. The lower courts reasoned that sovereign immunity only applies when the litigation would "divest the state of full ownership and eliminate all regulatory power over the submerged lands."

In the April 23 opinion, Circuit Judge Rachel Bloomekatz wrote: "Enbridge does not seek to extinguish the state's ability to exercise its regulatory and sovereign authority over the disputed lands entirely. Enbridge seeks only to bring the state's regulatory activities into compliance with federal law and the Constitution."

The Line 5 Legal Battle

Governor Whitmer and Attorney General Dana Nessel campaigned on promises to shut down Line 5, arguing that the 70-year-old oil pipeline poses too great a risk to the Great Lakes. The state initiated litigation between 2019 and 2020 after negotiations to speed up the construction of a tunnel to house the line failed.

In 2020, Whitmer revoked Enbridge's 1953 easement that allows the operation of the twin 20-inch underwater pipelines on the bottom of the Lake Michigan side of the Straits of Mackinac, west of the Mackinac Bridge. That revocation prompted Enbridge to file suit in federal court seeking an order to keep the pipeline running.

In late 2018, then-Governor Rick Snyder entered into an agreement with Enbridge, in which the Calgary, Alberta-based company promised to build a tunnel under the Straits of Mackinac to house a new segment of Line 5 and protect it from potential anchor strikes or other disturbances. Enbridge has secured most of its state permits for the tunnel but is waiting on the completion of a federal review before it can begin construction.

Other Legal Fronts

Aside from the lawsuits filed in relation to the pipeline, Canada invoked a never-before-used 1977 treaty in 2021 that prevents either country from taking actions in relation to a pipeline that may harm the energy supply in either country. Those negotiations are ongoing.

The U.S. Supreme Court also heard arguments in February over whether a separate lawsuit filed by Nessel seeking to shut down the pipeline was properly removed to federal court. Meanwhile, in the Michigan Supreme Court, the seven justices heard arguments earlier this month on a challenge to a permit Enbridge needs to build a tunnel to house a new segment of Line 5 in the straits.

"We will continue to fight for the people of Michigan on these vital issues concerning the Line 5 pipelines in the Straits," said Wimmer, adding that the state will pursue other avenues to protect the Great Lakes.

Enbridge spokesperson Ryan Duffy stated: "Line 5 is operating in accordance with federal law, interstate commerce regulations, and international treaty obligations. These frameworks recognize the essential role Line 5 plays in meeting the energy needs of the Great Lakes region and supporting its economic vitality."

Construction Already Underway

While Michigan loses this particular legal battle, Enbridge is moving forward with other Line 5 projects. The company has begun construction on its Line 5 reroute in northern Wisconsin, advancing the project despite ongoing legal challenges and environmental concerns.

Enbridge is voluntarily offering to reimburse local agencies for any project-related public safety and emergency response services, though this approach has raised concerns among communities that have seen significant costs with Enbridge's Line 3 reconstruction in Minnesota.

What's Next

The Supreme Court's denial forecloses Michigan's avenue of relief through that particular appeal, but multiple legal battles remain both on the substantive questions of law and the safety of the pipeline project. A separate case questioning the jurisdiction of the Line 5 legal fight is pending before the U.S. Supreme Court.

The Michigan Supreme Court's ruling in the tunnel permit case, which determines whether state regulators did enough to protect the environment when they approved the project, is expected in the coming months. The ruling will balance safeguarding the Great Lakes and keeping fuel flowing across the region.

For now, the lower court decisions stand as the final word on Michigan's sovereign immunity claim, allowing Enbridge to continue its legal and construction efforts to maintain operations of the Line 5 oil pipeline under the Straits of Mackinac.