When Whitney Gravelle saw reports earlier this week that President Biden might be considering the shutdown of Michigan’s controversial Line 5 pipeline, she was elated.

For years, she and other Native tribal members in the state had been fighting for the decommission of the 68-year-old fossil fuel pipeline, which they say has long violated their tribal rights and risks contaminating the Great Lakes and other lands that their communities depend on for their livelihoods and traditions.

The news reports, denied by White House officials, received fierce criticism from Republicans, who said shutting down such a vital fuel line would only exacerbate the country’s already surging natural gas prices.

While climate and Indigenous activists have applauded Biden’s decision to axe the Keystone XL Pipeline, he’s been widely criticized by the same groups for refusing to do the same with other major U.S.-Canada pipelines, such as Michigan’s Line 5 and Minnesota’s recently completed Line 3.

Owned by Canada-based Enbridge Energy, Line 5 plays a crucial role in Canada’s energy exports and oil refining industry, while also supplying the state of Michigan with more than half of its propane needs. The pipeline delivers up to 540,000 barrels of Canadian crude and other petroleum products every day from Superior, Wisconsin, to Sarnia, Ontario, passing through Michigan’s Upper Peninsula and under the Straits of Mackinac on the way.

Now Line 5 has become the latest symbol for a growing anti-fossil fuel movement in the United States, led by climate activists—who say the country’s network of oil and gas lines play a major role in the rapid warming of the planet—and by Indigenous communities, who warn that any potential spills threaten to contaminate lands where they fish, hunt and gather wild rice—rights guaranteed to them by past treaties.

The notion that President Biden might kill Line 5, the way he did with the Keystone XL pipeline earlier this year, was short lived. On Tuesday, White House officials confirmed that they were studying the possible economic ramifications of shutting down Line 5—as first reported last week by POLITICO—but said they had no intention of doing so.

Some energy experts say shutting Line 5 down would cause serious political tensions between the United States and its biggest trading partner, Canada. And the recent confusion only highlighted the delicate balancing act President Biden has been performing since taking office with pledges to tackle climate change and environmental injustice, while pursuing bipartisan cooperation. It also underscored the high stakes for the Biden administration, and for other Democrats, as they attempt to pass their massive domestic climate agenda.

As Biden touted America’s reentrance to the world stage as a leader in the global fight against climate change at COP26 last week, all 12 federally recognized Native tribes in Michigan urged the president to demonstrate his commitment to climate action and to uplifting underrepresented voices by supporting the state’s efforts to shut down Line 5.

“During your campaign, you promised that you would heed our concerns and act to protect our fundamental interests,” the tribes wrote in their Nov. 4 letter. “We view Line 5 as an existential threat to our treaty-protected rights, resources, and fundamental way of life as Anishinaabe people of the Great Lakes.”

Last year, Michigan Gov. Gretchen Whitmer appeared to agree with those arguments when she ordered Enbridge to shut down Line 5. In her notice of revocation and termination, Whitmer cited a state review that determined the pipeline is putting the Great Lakes at risk of contamination, as well as violating Native treaty rights. She took note specifically of the 1836 Treaty of Washington, which ceded Ojibwe and Odawa lands in Michigan to the federal government in exchange for fishing, hunting and gathering rights on the treaty territory.

Over the course of its lifespan, the pipeline has spilled more than 1 million gallons of oil and gas, according to a 2017 federal analysis. In 2018 and 2020, boat anchors struck and damaged Line 5 in the Straits of Mackinac, where the line passes between Lake Michigan and Lake Huron. And a 2016 study from the University of Michigan determined that a particularly bad spill from Line 5 could contaminate a significant portion of Lake Michigan and Lake Huron, spreading across more than 52 miles of shoreline in a matter of days.

Enbridge, however, has refused to comply with the order, and a lawsuit from the state’s attorney general to force Enbridge to comply is still working its way through the courts. But that case could be complicated by treaty negotiations between the U.S. and Canadian governments.

In early October, Canada’s government, disputing Michigan’s attempt to shut down Line 5,  invoked a decades-old international treaty with the United States regarding pipelines. The White House has said its information gathering on Line 5 has been in regard to the treaty talks.

In a statement, Enbridge said Line 5 continues to operate safely and that the company supports the sovereignty and treaty rights of tribal nations in Michigan. “There are millions of people and thousands of businesses on both sides of the border who are dependent on Line 5 to provide the fuel they need for heating, manufacturing, airplanes, roads and automobiles,” the company added.

Shutting down Line 5 could cause “major problems” with Canada, America’s most important energy partner, said Ben Cahill, the climate and energy analyst for the Center for Strategic and International Studies.

“The optics of shutting down Line 5 in this market with elevated prices would be really poor,” Cahill said. “The economic, political and diplomatic costs of shutting it down are just too big—they really outweigh any benefits.”

But Gravelle, who is also president of her tribe—the Bay Mills Indian Community, said it’s a legal and moral imperative that the Biden administration intervene. When Line 5 was built in 1953, Native tribes were never consulted on the matter. And the 1836 Treaty of Washington stands today as a living document, she said, not “just a history lesson.”

“When our ancestors signed those treaties, they understood that the documents they were signing were a sacred promise for the future for their children and their children’s children,” Gravelle said. “They knew that as long as we had these rights, as long as we could maintain that relationship with the land and water, that we would be able to continue to survive as a people”