(CNN) — The heated protests over the Dakota Access Pipeline appear to be approaching a final showdown.
After protesters refused to heed authorities’ demands to leave private property, North Dakota officials sought outside help to beef up their presence.
The Nebraska State Patrol responded and sent support, spokeswoman Deb Collins said. She said North Dakota, not Nebraska taxpayers, will pay for the aid.
The long-brewing conflict stems from protesters who say construction of the 1,172-mile pipeline will threaten the environment and destroy Native American burial sites, prayer sites and culturally significant artifacts.
But hundreds of protesters have trespassed onto private property in North Dakota, and some have vandalized construction equipment, authorities said.
“Protesters’ escalated unlawful behavior this weekend of trespassing onto private property and establishing an encampment has forced law enforcement to respond,” Morton County Sheriff Kyle Kirchmeier said.
“I can’t stress it enough — this is a public safety issue. We can not have protesters blocking county roads, blocking state highways, or trespassing on private property.”
More than 127 protesters have been arrested in the protests, including “Divergent” actress Shailene Woodley. Presidential candidate Jill Stein was charged with misdemeanors after video showed her spray-painting a bulldozer.
To fully understand the debate, here’s what you need to know about the pipeline:
What is the Dakota Access Pipeline?
It’s a $3.7 billion project that would cross four states and change the landscape of the US crude oil supply. Depending on who you ask, the results could be an economic boon that makes the country more self-sufficient or an environmental disaster that destroys sacred Native American sites.
The 1,172-mile pipeline, currently under construction, would stretch from the oil-rich Bakken Formation — a vast underground deposit where Montana and North Dakota meet Canada — southeast into South Dakota, Iowa and Illinois.
The oil potential in Bakken is massive. An estimated 7.4 billion barrels of undiscovered oil is believed to be in its US portion, according to the US Geological Survey.
After the pipeline is completed, it would shuttle 470,000 barrels of crude oil a day, developer Energy Access Partners said. That’s enough to make 374.3 million gallons of gasoline per day.
From Illinois, the oil could go to markets and refineries across the Midwest, East Coast and Gulf Coast.
Who approved it?
The US Army Corps of Engineers approved the project and granted final permits in July.
But the Standing Rock Sioux Tribe sued the Corps, saying the pipeline “threatens the Tribe’s environmental and economic well-being, and would damage and destroy sites of great historic, religious, and cultural significance to the Tribe.”
The Army Corps of Engineers has declined to comment to CNN, citing pending litigation.
But an advocacy group says the tribe’s claims are misleading, saying the pipeline “does not cross into the Standing Rock Sioux Tribe’s reservation.”
The Midwest Alliance for Infrastructure Now also said 100% of the affected landowners in North Dakota, where part of the tribe lives, voluntarily signed easements to allow for construction.
What’s the argument for and against?
Pro: The pipeline wouldn’t just be an economic boon, it would also significantly decrease U.S. reliance on foreign oil, the developer Energy Transfer Partners said. The pipeline would also help free up railways to transport “crops and other commodities currently constrained by crude oil cargos.”
Con: Construction for the pipeline will “destroy our burial sites, prayer sites and culturally significant artifacts,” the Standing Rock Sioux tribe said. Opponents also cite environmental concerns, including possible contamination due to breaches and eventual greenhouse gas emissions.
What’s the environmental impact?
Depends on who you ask.
The developer says the pipeline would provide a safer, more environmentally friendly way of moving crude oil compared to other modes of transportation, such as rail or trucks.
Pipeline supporters cite the 2013 disaster in Quebec, Canada, where a train carrying crude oil derailed and destroyed downtown Lac-Megnatic.
But Standing Rock Sioux Chairman David Archambault II said he doesn’t support moving more crude oil from North Dakota. He told CNN affiliate KFYR that Americans should look for alternative and renewable sources of energy.
More than 271,000 online petitioners agree.
“The Dakota Access pipeline would fuel climate change, cause untold damage to the environment, and significantly disturb sacred lands and the way of life for Native Americans in the upper Midwest,” a petition on CredoAction.com states.
Opponents also say they’re worried what would happen if the pipeline, which would go under the Missouri River, ruptured and contaminated the water supply.
But the Midwest Alliance for Infrastructure Now backed the developer’s claim that pipelines are a safe way of moving crude oil.
“Already, 8 pipelines cross the Missouri River carrying hundreds of thousands of barrels of energy products every day,” the group said in a statement.
What’s the economic impact?
Energy Transfer Partners estimates the pipeline would bring an estimated $156 million in sales and income taxes to state and local governments. It’ll also add 8,000 to 12,000 construction jobs, the developer said.
But Archambault said his tribe will settle for nothing less than the stop of the pipeline’s construction.
“We’re not opposed to energy independence. We’re not opposed to economic development,” he told CNN. “The problem we have — and this is a long history of problems that evolved over time — is where the federal government or corporations take advantage of indigenous lands and indigenous rights.”
What do the landowners get?
Energy Transfer Partners said it has tried to steer the pipeline away from residential areas and has tried to reach voluntary deals with property owners “at a fair price.”
But Archambault, the tribal chairman, said he thinks the Native Americans are getting short-changed once again.
“What we’re opposed to is paying for all the benefits that this country receives,” he said. Whenever there’s a benefit, whether it’s energy independence … whether it’s economic development, tribes pay the cost. And what we see now are tribes from all over sharing the same concern that we have, saying, ‘It’s enough now. Stop doing this to indigenous people. Stop doing this to our indigenous lands.'”