Over the weekend, the Obama administration denied a key permit necessary to complete the controversial Dakota Access pipeline.

This overtly political decision not only ignores the facts about the Dakota Access pipeline; more dangerous, the Obama administration has rewarded the violent tactics used by some of the pipeline’s most radical protesters.

Since the protests began, a staggering 566 people have been arrested for charges ranging from attempted murder to rioting to conspiracy to endanger by fire or explosion.

A 37-year-old Colorado woman allegedly fired her .38-caliber pistol three times at a sheriff’s deputy. She was arrested after a struggle, and law enforcement said they found marijuana on her person.

In addition to bullets, law-enforcement officials have dodged protesters’ other projectiles, which have ranged from Molotov cocktails to wood and stones to feces. A drone endangered a police helicopter, and the sheriff’s department said arrows were also shot at it.

The mob-like tactics haven’t ended there. In late September, pipeline security guards claimed that protesters had attacked them, brandishing a knife and a handgun in one incident. Signs for the pipeline were riddled with bullets, and private property had been defaced with spray paint, according to the sheriff’s department.

And in November, protesters on horseback chased a herd of bison, “attempting to stampede them toward law enforcement,” the sheriff’s department reported. It took a helicopter and an airplane to divert them, the situation veering close to catastrophe.

“It was a full-on stampede,” recounts a spokeswoman for the sheriff of Morton County, where the protesters have congregated. “People could have been killed.”

Tellingly, fewer than one in ten arrested in the protests actually live in North Dakota, near the pipeline’s most controversial juncture. From the beginning, far-left environmental groups and professional protesters have injected themselves into the fight over the Dakota Access pipeline.

Hyped from their Keystone XL victory, these green activists have sought to kill off any project that would facilitate the use of traditional energy sources.

They’ve used their social-media savvy to downplay their own violent tactics, claiming “police brutality” every time law enforcement restrains them. They’ve also waged a sophisticated social-media campaign, spreading misinformation and absolute falsehoods.

Centrally, the Dakota Access’s opponents claim that the pipeline endangers both the water supply and important Native American cultural sites.

But the U.S. Army Corps of Engineers pored over more than 1,200 pages of environmental and cultural analysis before issuing its initial permits. Moreover, 14 pipelines already traverse the Missouri River — and more than half of those are used to transport oil. While no transportation method is wholly without risks, pipelines have proven far safer than the rail and road routes used to transport Bakken Shale oil without the pipeline.

Cultural concerns are equally ill-founded. Specifically to avoid historic and cultural sites — even on private land — developer Energy Transfer adjusted the pipeline’s pathway 141 times.

Archeologists at both the National Register of Historic Places and the North Dakota Historic Preservation Office signed off on the carefully mapped route. The pipeline, which falls 99 percent on private lands, does not cross the Standing Rock Sioux’s reservation, contrary to popular belief.

Regardless of the facts, the Dakota Access pipeline has become a liberal cause célèbre, and the green-tinged Obama administration has decided to intervene. A federal judge had denied the tribe’s request for an injunction, even after paying special consideration to historic injustices against Native Americans.

Displeased with the court’s conclusion, three federal agencies ordered a work halt in September, even though permits to proceed had already been issued. In doing so, the Obama administration essentially decided to overrule an unpopular court decision.

That decision worried the chairman of the Morton County Commission. “Given the recent escalation of violence by protesters,” he told the Wall Street Journal, “letting the situation ‘play out’ is quite literally putting lives in danger.”

Which brings us to Sunday, when the Obama administration again intervened, rewarding protesters’ thug tactics, demanding more environmental reviews, and even suggesting that the pipeline — already under construction — may need to be rerouted.

Even under the most noble of circumstances, protesters lose their legitimacy when they resort to violence. By caving to the Standing Rock demonstrators, the Obama administration has sent the message that violence, intimidation, and vandalism yield results.