High Court Denies Michigan's Request to Block Enbridge Lawsuit
The U.S. Supreme Court has refused to hear Michigan's appeal in a landmark legal dispute over the Enbridge Line 5 pipeline, leaving in place lower court rulings that allow the energy company to sue the state over its efforts to shut down the controversial oil pipeline in the Straits of Mackinac.
According to the Detroit News, the high court denied Michigan's petition for review, meaning it will not consider whether Gov. Gretchen Whitmer and the state are shielded by sovereign immunity from Enbridge's federal lawsuit. That decision leaves in place lower court rulings that allow the lawsuit to proceed.
Attorney General Dana Nessel's office expressed disappointment with the decision, saying it limits the state's ability to assert its sovereignty in ongoing litigation. State officials had argued that the Eleventh Amendment protects Michigan from being sued in this case.
Federal courts have previously ruled that Enbridge's lawsuit can move forward because it alleges conflicts between Michigan's actions and federal law governing pipeline operations. A Sixth Circuit panel determined that the case does not strip the state of its regulatory authority, but instead seeks to ensure that state actions comply with federal law and the U.S. Constitution.
The dispute is part of a broader, years-long legal battle over the future of Line 5, a more than 70-year-old pipeline that runs beneath the Straits of Mackinac. Whitmer and Nessel have sought to shut down the pipeline over environmental concerns, including the risk of a spill in the Great Lakes. Enbridge has fought to keep the line operational and is pursuing plans to replace the underwater segment with a tunnel.
The Supreme Court heard arguments in February on a separate dispute over whether the case belongs in state or federal courts, but the justices declined to take up that matter as well.
"We are disappointed by the Supreme Court's decision not to review this important issue of state sovereignty," said Danny Wimmer, press secretary for Michigan Attorney General Dana Nessel. "We will continue to fight for the people of Michigan on these vital issues concerning the Line 5 pipelines in the Straits."
Enbridge spokesperson Ryan Duffy said the pipeline is already safe, but the tunnel will make Line 5 an even safer means of transporting crude oil and natural gas liquids through the region. "Line 5 is operating in accordance with federal law, interstate commerce regulations, and international treaty obligations," Duffy said in an email to Michigan Public Radio. "These frameworks recognize the essential role Line 5 plays in meeting the energy needs of the Great Lakes region and supporting its economic vitality."
Governor Directs State Agencies to Help Businesses Pursue Tariff Refunds
While the Supreme Court left the Line 5 case in federal court, Gov. Gretchen Whitmer moved quickly to assist Michigan businesses in pursuing refunds from tariffs imposed by the Trump administration that were recently struck down by the U.S. Supreme Court.
Whitmer's executive directive comes after a February Supreme Court ruling that found former President Donald Trump improperly used emergency powers to enact sweeping import tariffs. The decision has opened the door for companies that paid those tariffs to potentially seek refunds, though the process is still being developed at the federal level.
Whitmer's order instructs several state departments — including Agriculture and Rural Development, Labor and Economic Opportunity, Transportation and Treasury — to assess how the tariffs affected Michigan's economy and report their findings within 30 days. State officials say ensuring access will be especially important for smaller businesses that may lack legal or financial resources to navigate complex claims.
The order emphasizes making the process accessible to all eligible importers. State officials have also linked tariffs to higher consumer costs, estimating the average Michigan family paid about $1,000 more per year due to price increases. Federal officials are still building a system to process refund claims, which could take several weeks once fully operational.
"Tariffs imposed by Republicans in Washington have raised costs for many sectors of Michigan's economy," Whitmer wrote in Executive Directive 2026-2. "Those reports revealed that tariffs increased the price of raw materials, raised production costs, and restricted market access for our products."
Some companies absorbed the costs, but many passed them along through higher prices, reduced investment, or slower hiring. Retaliatory tariffs from trading partners have also hurt Michigan exporters, particularly in agriculture. Michigan farmers selling soybeans, dairy, and other products abroad faced reduced demand when countries like China imposed counter-tariffs on U.S. goods, lowering farm revenues and creating uncertainty in rural communities.
For working families, tariffs have cost each family on average $1,000 per year. They have led to higher prices for cars, appliances, construction materials, and consumer products. U.S. consumers and businesses have borne most of the cost of these tariffs rather than foreign producers.
In a state where many households depend directly or indirectly on manufacturing and agriculture, these price increases squeezed family budgets while also threatening job stability in key industries. The combined effect has been slower economic growth in tariff-exposed sectors and added financial pressure on Michigan households already managing rising living costs.
The pain of these increased costs has not been offset by any of the promised economic gains. U.S. GDP grew at a slower rate in 2025 than in preceding years, and companies added fewer jobs in 2025 than at any point in the last 20 years. Michigan's industries have been hit hard, with a recent analysis finding that the tariffs cost U.S. automakers $35 billion last year.
Recently, the U.S. Supreme Court ruled unconstitutional the tariffs imposed solely by the executive under the International Emergency Economic Powers Act (IEEPA) without Congressional action. While the administration has assured the federal courts that they have set aside the $166 billion in unconstitutional tariffs, they have yet to establish a process for returning those funds.
Despite the uncertainty and disruption driving up prices in our economy and the lack of any Congressional involvement, the administration has not backed down on its use of tariffs. In fact, the administration has imposed new tariffs following the Supreme Court's ruling, as well as maintaining those on steel, aluminum, and other goods.
"Michigan's businesses and residents will continue to pay for this costly policy," Whitmer said.
What Comes Next for Line 5?
With the Supreme Court's refusal to hear Michigan's appeal, the Line 5 legal battle continues in federal court. The state remains committed to protecting the Great Lakes from potential pollution, while Enbridge maintains that the pipeline is safe and that its proposed tunnel project will make it even safer.
The tunnel would be approximately four miles long and run beneath the Straits of Mackinac near the Mackinac Bridge. Enbridge says the project is necessary to maintain safe operations over the coming decades. The company has invested heavily in upgrading Line 5, including installing new sensors and monitoring systems.
State officials argue that the environmental risk of a spill in the Straits — which connect Lake Michigan and Lake Huron — is too great to continue operating two parallel pipelines in the water. The state has cited decades of federal studies that say Line 5 does not meet modern environmental standards for Great Lakes waterways.
As the legal battle continues, both sides will likely focus on the substantive questions of pipeline safety and regulatory authority rather than procedural immunity claims. Michigan's Supreme Court may still have other opportunities to weigh in on the case, particularly if new legal arguments emerge in lower courts.
Related Developments
In other Michigan Supreme Court news, the high court will hear a legal dispute between House Republicans and Senate Democrats over whether nine bills passed during the previous legislative session must be formally delivered to Gov. Gretchen Whitmer. The dispute centers on legislation approved at the end of the 2023-24 session, when Democrats controlled both chambers, but never presented to the governor after Republicans took control of the House in 2025.
The court issued an order March 27 indicating it will take up the case, with oral arguments expected in May. House Speaker Matt Hall, R-Richland Township, has argued that the new Republican majority is not obligated to complete unfinished administrative steps from a prior Legislature. Democrats, led by Senate Majority Leader Winnie Brinks, D-Grand Rapids, maintain that presenting passed bills to the governor is a routine procedural duty.
Additionally, in a separate development, Whitmer declared a statewide energy emergency Thursday, issuing an executive order that temporarily eases fuel regulations as costs rise due to global instability. Executive Order 2026-4 suspends certain seasonal fuel requirements in parts of southeast Michigan, allowing gas stations to sell higher vapor pressure gasoline, which is typically cheaper to produce and purchase.
The change aligns Michigan with a temporary waiver issued by the U.S. Environmental Protection Agency and is expected to reduce pump prices by an estimated 10 to 20 cents per gallon. The order applies to eight counties — Wayne, Oakland, Macomb, Washtenaw, Livingston, Monroe, St. Clair and Lenawee — home to roughly 5 million residents.
Whitmer said the move is intended to provide immediate relief as gas prices climb sharply, citing disruptions in global oil markets tied to the ongoing conflict in Iran. According to the administration, average gas prices in Michigan have risen to about $3.89 per gallon, up roughly 30% from earlier levels.
While the governor acknowledged state leaders cannot control global energy markets, she said the executive order is one step the state can take to ease pressure on household budgets. The order also directs consumers to report potential fuel quality issues to the Michigan Department of Agriculture and Rural Development, which oversees fuel standards and enforcement.