The Standing Rock Sioux tribe is taking their next step in the battle against the Dakota Access Pipeline after the Army Corp of Engineers gave the corporation the go-ahead to complete the pipeline in defiance of President Obama’s order for an environmental impact survey.

On Tuesday, the Acting Secretary of the Army instructed the Army Corp to allow the pipeline to proceed, and the Standing Rock officials said that if Trump ordered the environmental order be ignored, he would be in direct violation of the law.

North Dakota senator John Hoeven also supported the override, assuring constituents that the president would be finishing the pipeline shortly.

Said Standing Rock Sioux officials:

“The Standing Rock Sioux Tribe will vigorously pursue legal action to ensure the environmental impact statement order issued late last year is followed so that the pipeline process is legal, fair and accurate.”

The tribe called the decision an arbitrary one based solely on the president’s personal views, and said that  many steps must be taken before the pipeline can be legally completed.

According to TYT Politics reporter Jordan Chariton who has followed every move made at Standing Rock these last few months, the move by the Army Corp of Engineers and the corporation are illegal because once ordered, an environmental impact survey must be completed before a project can proceed.

The environmental impact statement was issued by Obama at the end of 2016 and was viewed as the one positive environmental move the former president had made to protect the environment from President Trump. At the time, it was expected that the environmental impact order was unbreachable, giving those at Standing Rock more time to prepare for the next battle.

Regardless, the Sioux tribe of water protectors say that they are ready to fight with every resource available to them to stop the Dakota Access Pipeline once more – this time for good.