From peaceful protests to chaotic marches - and from a camp of thousands to a street protest of hundreds: The Dakota Access Pipeline stirs strong emotions.

“This is my ancestral land – this is my Ireland, this is my Italy, this is my Africa. This is our land,” Simon Moya-Smith of Denver said, who is Oglala Lakota and one of a number of Coloradans who traveled to North Dakota to join the protest.

For more than seven months, several thousand people have gathered in North Dakota near the remote Standing Rock Sioux Reservation to protest the oil pipeline. The argument is over danger to the water supply and Native American rights.

“We’re taking a stand right now towards the Dakota Access Pipeline. They’re getting toward the Missouri River and that’s what will happen when the pipe leaks, it’ll contaminate the drinking water for the people.”

There are several issues at play here. One is that the pipeline will pass through sacred, historic sites and part of the watershed of the Missouri River, which is the reservation’s source of drinking water. The other argument is that the pipeline is going through land that once belonged to these Native Americans under a treaty from 1851. It’s a treaty that legal experts say, depending on how you look at it, was either “breached” or “renegotiated” several times since then.

On top of that, the original pipeline route had it going much closer to more populated areas closer to Bismarck. However, concerns about potential water contamination there pushed it farther south, closer to the Standing Rock Sioux Reservation.

Sarah Krakoff is a law professor at CU Boulder, who specializes in the areas of federal and tribal law.

“Legally speaking, the claims that the Standing Rock has against the federal government are federal statutory claims, based on the Clean Water Act, the National Environmental Policy Act and the National Historic Preservation Act,” Krakoff said.

Yet, would those be strong enough to stop the Army Corps of Engineers from granting a permit for that final section of the pipeline?

“The federal government in all of its actions, with respect to tribes, including Standing Rock, is supposed to exercise what’s called a ‘trust relationship’ on behalf of the tribe. So, they’re supposed to take account of the tribes’ interests in a whole range of decisions they make that might affect the tribe,” Krakoff said. “Both of those kinds of arguments: ‘this was our land and you breached the treaty’ and ‘you have a trust obligation’ are not all that strong in terms of their ability to be enforced through litigation.”

Energy Transfer, the company behind the pipeline, did not respond to our requests for comment. However, in a previous statement, the company said the pipeline construction has created more than eight thousand jobs and, when it’s finished, would help move nearly half a million barrels of oil across four states every day.

However, Moya-Smith said, the opposition to it will continue.

“They’re not looking out for the water,” he said.

For now, the permit is on hold, but no matter what the Army Corps of Engineers decides, it could all end up before a federal judge, who may have the final say.