The fight over the Dakota Access pipeline is not over yet, despite the Armed Corps of Engineers' denial to approve permits needed to complete the $3.7 billion, 1,172-mile project, maverick Sen. Heidi Heitkamp of North Dakota told CNBC on Monday.
"When you look at it, we know one thing for sure: When the administration changes, the easement is going to be approved," Heitkamp told "Squawk Box," referring to the legal right pipeline proponents are claiming to justify construction on Native American land.
"I understand the frustration of the protesters, I just think that this fight is not winnable," said the senator, adding that she hopes to continue her work to improve living conditions for Native American communities.
Heitkamp has advocated for a more positive approach on U.S. energy policy while in the Senate, pushing for heightened domestic production and North American energy independence.
"We spent a lot of time talking about economic development, talking about energy, talking about regulation and what we need to do there, so it really was a very substantive discussion without a lot of details on positions in the Cabinet," she said.
Heitkamp said the two spoke a lot about jobs and highlighted Trump's "myopic focus on how he's going to get American workers back into the workplace [and] provide more economic security."
The Army announced its decision on Sunday, giving a victory to the Standing Rock Sioux tribe and its supporters, who argued the project would threaten the tribe's water source and cultural sites. Assistant Secretary for Civil Works Jo-Ellen Darcy said in a statement that her decision was based on the need to "explore alternate routes" for the pipeline's crossing of the Missouri River. Her full decision doesn't rule out that it could cross under the site or north of Bismarck.
North Dakota's leaders criticized the decision, with Gov. Jack Dalrymple calling it a "serious mistake" that "prolongs the dangerous situation" of having several hundred protesters who are camped out on federal land during cold, wintry weather. U.S. Rep. Kevin Cramer said it's a "very chilling signal" for the future of infrastructure in the United States.
Before Heitkamp became a senator, she was director of a Dakota Gasification plant, the only commercial-scale synthetic natural gas producing company in the United States.
— The Associated Press contributed to this story.