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SACRAMENTO (CBS13) — It was their oath to protect and serve that brought thousands of U.S. veterans to North Dakota, including several dozen from the Sacramento area.

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“We fought for this country and we took a vow to protect it from enemies, foreign and domestic. This is as domestic as you get,” said Robin cage, referring to those behind the Dakota Access Pipeline.

Cage headed up the California contingent of military veterans, who joined the Sioux nation and other Native American tribes last week, in protest of pipeline’s construction.

The $3.8 billion pipeline project runs almost 1,200 miles from the Bakken Shale in North Dakota to Illinois. It is almost complete, except for a small section that will go under the Missouri River.

Like many, their concern is that pipeline will adversely impact drinking water and disturb sacred tribal sites.

Energy Transfer Partners, who is building the pipeline, says it will further reduce Americans dependence on foreign oil, create thousands of jobs and create revenue at the local and state level.

Last week, over 4,500 vets showed up from around the country. “It was tense, very tense. And there was a lot of anger,” shared Cage.

Together, they marched in the freezing cold and massive blizzard to the pipeline construction site, and then crossed a bridge over the Missouri River – a bridge that had been previously off limits to the local tribes, until the vets showed up.

“We came to protect and we were expecting a rubber bullets, and mace, and there was nobody. We get to the bridge. Gone. The mountain ridge. Gone. All the police were gone. So, I think we made a big difference,” said Cage.

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Part of the reason for the lack of police resistance was the massive blizzard that swept in and eventually forced mandatory evacuations. But the Army Corps of Engineers, who is responsible for issuing permits for the project, also denied the final permit to finish the project, at the direction of the Obama administration – one day before the veterans arrived. The government wants a further environmental review.

Jesse Solo, a Navy veteran and Sacramento resident, also made the trip to North Dakota. He joined the military after 9-11.”The oil companies are pretty much the cause of most conflict in the world and our dependence on oil,” he said.

He believes the presence of U.S. veterans played a role in delaying the pipeline’s construction.

“In politics, veterans seem to matter more (than Native Americans). And it’s bad PR to be tear gassing and shooting veterans with rubber bullets,” explained Solo.

After spending a few days in in North Dakota, for Solo, like many other, it began the protest began to take on a spiritual dimension and grew to more than just politics and a pipeline.

“This is like the spearhead of the battle between sustainability and the old ways of using resources, acting like we will have them forever,” said Solo.

Solo recounted a story of a tribal elder, who compared humans need for fossil fuel to the need for water. “Nobody can live without water,” said Solo, meaning the concern for healthy water should trump any need for oil.

Despite the permit being denied, construction has not stopped. And Energy Transfer Partners has good reasons to rush to finish. Any rerouting of the pipeline would require them to get additional easements from other property owners.

Plus, more delays could end a deal the company already has to sell a $2 billion minority stake in the project if they don’t finish by January.

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As for the local veterans, a few of them are planning to go back in January. You can help by contributing their GoFundMe account: AJourneyToStandingRock.