The Obama administration late Sunday punted on the controversial $3.8 billion Dakota Access oil pipeline (DAPL), denying a final easement to cross under Lake Oahe in North Dakota, choosing instead to seek alternative routes to satisfy concerns of the Standing Rock Sioux Tribe.

In a filing with the U.S. District Court of the District of Columbia, the U.S. Army Corps of Engineers signaled that it would not issue the outstanding easement required by the nearly 1,200-mile, four-state pipeline, which is 80% completed.

After delaying the decision in November, the Corps cited requirements of the Minerals Leasing Act as the reason for undertaking a new National Environmental Policy Act (NEPA) review on alternative routes. The Corps’ Jo-Ellen Darcy, assistant secretary for civil works, said, "Although we have had continuing discussion and exchanges of new information with the Standing Rock Sioux and Dakota Access, it's clear that there's more work to do.

“The best way to complete that work responsibly and expeditiously is to explore alternate routes for the pipeline crossing." Considering alternative routes would be best accomplished through an environmental impact statement with full public input and analysis, she added.

"We wholeheartedly support the decision of the administration and commend with the utmost gratitude the courage it took on the part of President Obama, the Army Corps, the Department of Justice and the Department of the Interior to take steps to correct the course of history and to do the right thing," said Standing Rock Sioux Tribal Chairman Dave Archambault II. He said the tribe hoped that pipeline sponsors, North Dakota Gov. Jack Dalrymple and the incoming Trump administration "respect this decision and understand the complex process that led us to this point. When it comes to infrastructure development in Indian Country and with respect to treaty lands, we must strive to work together to reach decisions that reflect the multifaceted considerations of tribes.

"Treaties are paramount law and must be respected, and we welcome dialogue on how to continue to honor that moving forward. We are not opposed to energy independence, economic development, or national security concerns but we must ensure that these decisions are made with the considerations of our Indigenous peoples."

But pipeline sponsors Energy Transfer Partners LP (ETP) and Sunoco Logistics Partners LP (SXL) called the Obama administration's decision "a purely political action -- which the administration concedes when it states it has made a 'policy decision' -- Washington code for a political decision. This is nothing new from this administration, since over the last four months the administration has demonstrated by its action and inaction that it intended to delay a decision in this matter until President Obama is out of office.

"For more than three years now, Dakota Access Pipeline has done nothing but play by the rules. The Army Corps of Engineers agrees, and has said so publicly and in federal court filings. The Corps’ review process and its decisions have been ratified by two federal courts. The Army Corps confirmed this again...when it stated its 'policy decision' does not alter the Army's position that the Corps’ prior reviews and actions have comported with legal requirements."

ETP and SXL went further.

"In spite of consistently stating at every turn that the permit for the crossing of the Missouri River at Lake Oahe granted in July 2016, comported with all legal requirements, including the use of an environmental assessment, rather than an environmental impact statement, the Army Corps now seeks to engage in additional review and analysis of alternative locations for the pipeline," they said. "The White House's the Corps for further delay is just the latest in a series of overt and transparent political actions by an administration which has abandoned the rule of law in favor of currying favor with a narrow and extreme political constituency.

"As stated all along, ETP and SXL are fully committed to ensuring that this vital project is brought to completion and fully expect to complete construction of the pipeline without any additional rerouting in and around Lake Oahe. Nothing this administration has done today changes that in any way."

A spokesman for President-elect Trump said, “With regard to the Dakota Access Pipeline, that’s something that we support construction of and we’ll review the full situation when we’re in the White House and make the appropriate determination at that time.”

Karen Harbert, CEO of the U.S. Chamber's Institute for 21st Century Energy, said the Obama administration had "sent a clear message...if your special interest-funded protest is loud enough and has enough celebrities tweeting their support, then the rule of law and the facts no longer matter. By capitulating to protesters, the Obama administration is putting an exclamation point on its eight year record of anti-growth energy policies.

"The Army Corps decision to deny the Dakota Access pipeline a final easement will only embolden special interest groups to continue their deceptive tactics, while scaring off job creators who are looking for opportunities to invest in America. Just as it did when it denied the Keystone XL pipeline, the administration is ignoring logic and an extensive review process in favor of extreme ideology. In this case, the Army Corps had already recommended approval of the easement after spending over 800 days reviewing the project.

"We are considering all potential remedies and look forward to the rule of law being reestablished as soon as possible," Harbert said.

National Association of Manufacturers CEO Jay Timmons said the action "defies logic, science and sound policy-decision making, and the consequences can be measured in lost work for manufacturers and those in the manufacturing supply chain."

Midwest Alliance for Infrastructure Now (MAIN) spokesperson Craig Stevens said the denial of an easement is "a politically motivated action with a complete disregard for the rule of law and the regulatory process that was so carefully followed over two years. To deny the easement, based on the influence and unlawful actions of the 'unpeaceful' protesters I saw firsthand is baffling and unlike anything I have ever seen."

The Army Corps' decision comes ahead of a status conference scheduled Friday, according to Christi Tezak, managing director of ClearView Energy Partners LLC. She previously said she assumed that the Trump administration could eventually issue an outstanding approval for the easement rather quickly, but now that is unclear. What the Corps apparently did on Sunday was fail to find it appropriate to issue an easement without completing additional NEPA review, she said.

"It’s not clear this precludes an approval of the route under Lake Oahe by the Trump administration, but we expect that the pathways to getting there may take longer," Tezak said.

In the meantime, Monday was the deadline for protesters to disband their camps in North Dakota after weeks of escalating conflict between pipeline opponents and law enforcement.

Environmental groups were cheering the decision. As the extreme Dakota winter sets in many of the pipeline opponents who have come from other areas of the country are expected to abandon their camps. If there were to be a later mid-winter decision clearing the way for construction, it would meet with less resistance.

Lindsey Allen, executive director of the Rainforest Action Network, said the latest action denying an easement demonstrates "what is possible when the environmental movement takes leadership from Indigenous (Native American) communities. We know we are entering a period of great uncertainty and that a strong and effective environmental movement is needed, now more than ever."