In the wake of the Obama administration’s surprise decision to block a portion of the Dakota Access Pipeline, company reps seem confident they need only wait for President-elect Trump to keep building. But the lawyer who represents the Standing Rock Sioux says it won’t be so easy to overcome the legal hurdles.

“If an agency decides that a full environmental review is necessary, it can’t just change its mind with a stroke of a pen a few weeks later,” EarthJustice attorney Jan Hasselman told Grist. “That would be violation of the law, and it’s the kind of thing that a court would be called upon to review. It doesn’t mean they’re not going to try.”

Trump could force the pipeline through along the disputed route at Lake Oahe. He technically could ignore the Corps’ decision to conduct a public Environmental Impact Statement with his newfound executive powers, but that might not be wise.