This might seem particularly odd when you consider the region’s history. The land beneath the pipeline was accorded to Sioux peoples by the Treaty of Fort Laramie in 1868. Eleven years later, the U.S. government incited and won the Great Sioux War, and “renegotiated” a new treaty with the Sioux under threat of starvation. In that document, the tribe ceded much of the Laramie land, including the Black Hills of South Dakota, where many whites believed there to be gold.

In the decades that followed, other land previously controlled by the Sioux was doled out by the federal government as homesteads to Native families; when those farms failed, the government often repossessed the land. And in 1980, the Supreme Court ruled that the Black Hills were taken unjustly, and it ordered the U.S. government to compensate the Sioux tribes fairly for them. But the Sioux declined the payment—which still sits in U.S. Treasury accounts, earning interest—because they seek possession or co-ownership of the land itself.

Of course, this history does not answer whose land it really is: American law still respects the underlying logic of the “doctrine of discovery,” the idea that European Christians could lay claim to land if they were the first to document it. But it is in partial recognition of the painful history of colonial land grabs that modern federal law accords certain rights to Native groups. Since 1992, one of these rights could be described as the right to be consulted: Whenever a federal agency undertakes or approves a construction project, it must consult with local Native nations or tribes about whether sacred sites or places are nearby.

This right must be respected even if the project isn’t near reservation land. In fact, in a bit of federal rule-making worth reading in full, the committee that oversees historic preservation on behalf of Congress explicitly decrees that “regulations require Federal agencies to consult with Indian tribes when they attach religious and cultural significance to a historic property regardless of the location of that property”:

The circumstances of history may have resulted in an Indian tribe now being located a great distance from its ancestral homelands and places of importance. It is also important to note that while an Indian tribe may not have visited a historic property in the recent past, its importance to the tribe or its significance as a historic property of religious and cultural significance may not have diminished for purposes of Section 106.

Crucially, as well, federal agencies must approve projects in a “government-to-government” way. A local tribe is not supposed to be hustled in at the end for a rubber stamp, but included throughout the process as a collaborative body.

It is this right—the right to be consulted—that the Standing Rock Sioux and their legal team assert was infringed. The Army Corps of Engineers must approve and permit any interstate pipeline. The tribe alleges that not only was the permitting of Dakota Access rushed, but also that the tribe itself was not included as partners through the historical surveying process. Only near the end of the process, when approval seemed inevitable, did North Dakota state authorities approach the tribe with a couple areas of concern. They did not present plans for the pipeline at the beginning, as government-to-government negotiations should entail.