A Minnesota appeals court on Monday sided with regulators who approved a controversial new section for an oil pipeline passing through the state.

In a 2-1 ruling, the court sided with the state Public Utilities Commission, which had given Canadian company Enbridge Energy the go-ahead on the pipeline’s Minnesota segment.

The proposed 337-mile section has drawn fierce opposition from a coalition of conservationists and tribal groups. The groups, along with the state Department of Commerce, argued in court that Enbridge had not properly demonstrated sufficient demand for oil to build that part of the pipeline. More than a thousand protesters gathered last week in Northern Minnesota to oppose the line’s construction.

In Monday's ruling, Judges Lucinda Jesson and Michael Kirk wrote that both the existing, “deteriorating” Line 3 segment and the construction of a new one pose environmental risks.

“There was no option without impacts on the rights of indigenous peoples. The challenge: to alleviate those harms to the extent possible,” they wrote. “And there was no crystal ball to forecast demand for crude oil in this ever-changing environment.”

“When balancing harms and predicting future demand, the commission is due deference. It is the agency tasked with these difficult decisions,” the two judges continued. “With this deference in mind we affirm the commission’s adequacy … and its decisions to issue a certificate of need and routing permit for the Line 3 replacement.”

In a dissent, however, Judge Peter Reyes wrote that the commission had “acted arbitrarily  or capriciously” and granted Enbridge “a certificate of need that is unsupported by substantial evidence.”

Reyes said the agency had misinterpreted statutory definitions of energy demand forecasts, and did not properly analyze whether there would be demand specifically in Minnesota for the oil supplied by the pipeline. He further argued that it failed to incorporate environmental risks into its decision.

“The [Public Utilities Commission] approved a new pipeline that benefits Canadian oil producers but traverses 340 miles of Minnesota land, which among other negative consequences will affect hunting, fishing, and other rights of relators Red Lake Band of Chippewa Indians and White Earth Band of Ojibwe, with no benefit to Minnesota,” Reyes wrote.

The Line 3 pipeline, part of a $9 billion expansion approved by the Army Corps of Engineers during the Trump administration, would carry nearly 800,000 barrels a day of tar-sands oil from Northern Minnesota into Wisconsin.

The fight over the project has intensified since Keystone XL announced last week it would abandon that pipeline, emboldening environmental and tribal activists.

In a statement after the decision, Vern Yu, Enbridge executive vice president and president of liquids pipelines, said: "After six years of community engagement, environmental review, regulatory and legal review, it's good to see confirmation of previous decisions on the Line 3 Replacement Project. From the start, the project has been about improving safety and reliability for communities and protecting the environment."

Tara Houska, founder of Giniw Collective, a tribal advocacy group that has led opposition to Line 3, called the pipeline "an abomination to climate science and human rights” and said efforts to halt it would continue.

“Our resistance is clearly growing,” she said in a press call after the court ruling. “We cannot stop and we will not stop."