The increasingly tense standoff over the Dakota Access Pipeline in North Dakota boils down to a clash between economic and cultural interests.
For North Dakota and the oil industry, the 1,172-mile pipeline is critical to bringing a prized resource to Gulf Coast and Midwest markets in a way that is less expensive and safer than rail.
"It's the interstate highway for Bakken oil," said Ron Ness, president of the North Dakota Petroleum Council, a trade group.
For the Standing Rock Sioux Tribe and tribes across the country, the $3.7 billion pipeline is an affront to native water rights and cultural heritage, the latest in a long history of assaults on tribal sovereignty.
"At some point, you have to take a stand," said Laura Waterman Wittstock of Minneapolis, a Seneca Indian who hosts a weekly American Indian news show on KFAI radio.
The pipeline, which crosses four states, is 92 percent complete — a key exception being the contested water crossing near the Standing Rock reservation in North Dakota. Protests there by American Indians and climate change activists are at a crescendo.
Law enforcement has used water hoses, tear gas and rubber bullets to disperse crowds in the past 10 days. North Dakota's governor and the Army Corps of Engineers have ordered the evacuation of some 5,000 protesters.
The dispute is rooted in the fracking revolution that transformed North Dakota into the nation's second largest petroleum producer after Texas. It's been a boon for North Dakota's economy, despite the slump in oil prices.