Labor unions on Monday alerted President Obama to what they consider to be a gross error by his administration in interfering last month with the construction of the $3.8 billion Dakota Access oil pipeline at a time when the courts are still sorting out lawsuits by the backers and opponents.

On Wednesday oral arguments are to be heard in the U.S. Court of Appeals for the District of Columbia Circuit. A lead plaintiff in the court case, Dave Archambault II, chairman of the Standing Rock Sioux Tribe, said Tuesday the Native American protesters “will not back down from this fight; we will not rest until our lands, people, waters and sacred sites are permanently protected from this destructive pipeline.”

The heads of five unions, including the Laborers International Union of North America (LiUNA), urged Obama to “adhere to the well-established regulatory process” that applies to private-sector infrastructure projects. In this case, Dakota Access needs a previously approved federal easement for a water crossing issued “without delay.”

Claiming to represent nearly 3.5 million workers, 8,000 of which are working on the four-state construction of Dakota Access, the union heads raised concerns about the future of infrastructure development in the United States if the Obama administration continues to hold up a major project that is more than half built and for which its federal permits were issued in July.

The project was “lawfully permitted and approved earlier this year after more than two years of review by the states of North Dakota, South Dakota, Iowa and Illinois, as well as the U.S. Army Corps of Engineers [USACE],” the union heads said. “It obtained more than 200 required permits and hundreds of easements for private and public lands.”

Oral arguments will be heard in the U.S Appeals Court in Washington, DC, Wednesday as part of a review of a 58-page ruling last month by U.S. District Court Judge James Boasberg, who concluded that the USACE “has likely complied” with the National Historic Preservation Act to assess the impact the oil pipeline’s construction could have on cultural sites in North Dakota (see Shale Daily, Sept. 9).

A coalition of pipeline supporters, the Midwest Alliance for Infrastructure Now (MAIN), on Monday cited a NYU law professor’s assessment that opponents of the pipeline are unlikely to win in the U.S. appeals court.

The union heads called Judge Boasberg’s decision “thorough” and expressed deep concerns at the decision of the Departments of Justice and Interior, along with USACE, to intervene subsequently and delay the project. They asked Obama to “stand up for American workers, American infrastructure, and the federal civil servants who completed the thorough and thoughtful analysis” of the pipeline over a two-year period.

Signing the letter were LiUNA’s Terry O’Sullivan; James Callahan with the International Union of Operating Engineers; James Hoffa with the International Brotherhood of Teamsters; William Hite of the United Association; and Lonnie Stephenson with the International Brotherhood of Electrical Workers.

According to MAIN, the current focus is on an already-approved 1,000-foot portion of the nearly 1,200-mile pipeline route. Dakota Access is 70% completed and more than $2.6 billion has been spent. The effort is supported by more than 8,000 union jobs.

“MAIN continues to believe that as long as the final [Obama] administration and judicial decisions are based on the facts, science, engineering and the rule of law, Dakota Access pipeline will be allowed to become operational without additional delay.”