Protesters demonstrate against the Dakota Access oil pipeline

More than a thousand people gather at an encampment near North Dakota’s Standing Rock Sioux reservation on Sept. 9, 2016.

Phil Daw Sr., of Albuquerque, New Mexico, helps cook beef stew to feed hundreds at an encampment near North Dakota’s Standing Rock Sioux reservation on Sept. 9, 2016.

A volunteer sorts through donated food near the Standing Rock Sioux Reservation in North Dakota on Sept. 14, 2016. Tribal officials say donated food and clothing has come from around the world to support those opposing the $3.8 billion Dakota Access pipeline.

Volunteers toss logs at an oil pipeline protest encampment near the Standing Rock Sioux Reservation in southern North Dakota on Sept. 14, 2016. The logs will be used to cook meals for the thousands of people who have come to the area to fight the $3.8 billion Dakota Access pipeline.

A traditional Aztec dancer looks on during a rally on Sept. 13, 2016, in San Diego, Calif., in support for the pipeline protestors in North Dakota.

Members of the Kupa Tribe from the Pala Indian Reservation hold an American flag during a rally on Sept. 13, 2016, in San Diego, Calif., in support of the pipeline protesters in North Dakota.

Sen. Bernie Sanders greets Jasilyn Charger, a member of the Cheyenne River Sioux tribe, after Charger spoke to a group of supporters of the Standing Rock Sioux rallying near the White House in opposition of the Dakota Access oil pipeline on Sept. 13, 2016, in Washington. Sanders also spoke at the rally.

A demonstrator raises his first next to a placard as protesters gather in front of the White House on Sept. 13, 2016, to protest the Dakota Access pipeline.

People hang out in the bed of their truck as the sun sets Sept. 3, 2016, over a protest encampment near Cannon Ball, North Dakota where members of the Standing Rock Sioux tribe and their supporters have gathered to voice their opposition to the Dakota Access oil Pipeline (DAPL).

A Standing Rock Sioux flag flies over a protest encampment near Cannon Ball, North Dakota where members of the Standing Rock Sioux tribe and their supporters have gathered to voice their opposition to the Dakota Access oil Pipeline (DAPL), Sept. 3, 2016.

Members of the Standing Rock Sioux Tribe and their supporters opposed to the Dakota Access Pipeline (DAPL) confront bulldozers working on the new oil pipeline in an effort to make them stop, Sept. 3, 2016, near Cannon Ball, North Dakota.

Flags of Native American tribes from across the US and Canada line the entrance to a protest encampment near Cannon Ball, North Dakota where members of the Standing Rock Sioux Tribe and their supporters have gather to voice their opposition to the Dakota Access Pipeline (DAPL), Sept. 3, 2016.

Members of Colorado River Indian tribes arrive in a procession at a protest encampment near Cannon Ball, North Dakota to lend their support to the Standing Rock Sioux Tribe’s opposition to the Dakota Access Pipeline (DAPL) Sept. 3, 2016.

A sign welcomes visitors at the entrance to an oil pipeline protest encampment near Cannon Ball, North Dakota where members of the Standing Rock Sioux tribe and their supporters have gathered to voice their opposition to the Dakota Access Pipeline (DAPL), Sept. 3, 2016.

Women and girls from the Colorado River Indian tribes dance after arriving at a protest encampment near Cannon Ball, North Dakota to lend their support to the Standing Rock Sioux Tribe’s opposition to the Dakota Access Pipeline (DAPL) Sept. 3, 2016.

A protester holds a sign reading Protect Our Water as Native Americans and their supporters walk on land designated for the Dakota Access Pipeline (DAPL), after protestors confronted contractors and private security guards working on the oil pipeline project, forcing them to retreat, Sept. 3, 2016, near Cannon Ball, North Dakota.