They are used to standing shoulder to shoulder in the face of adversity fighting for their country. But next weekend, hundreds of veterans will come together again, potentially for one last time. Their mission this time is not to fight for their Government. But against it.

With a heavy heart, but with a growing sense of outrage at what has been happening in North Dakota, on December 4, hundreds of veterans will congregate at the Standing Rock Sioux reservation to stand in solidarity with First Nations in their fight to stop the Dakota Access pipeline.

The unaceptable violence – including rubber rullets, pepper spray, stun grenades and water cannons – being deployed against the First Nations and other water protectors is now making news around the world.

After the events of last Sunday, one water protector, Sophia Wilansky, might even lose her arm after being hit by a stun grenade.

The escalating violence against the protectors is one of the main issues that has galvanised the veterans into action. One social media post this month said: “First Americans have served in the Unites States Military, defending the soil of our homelands, at a greater percentage than any other group of Americans. There is no other people more deserving of veteran support.”

The organiser of the event, a former Army officer is Wes Clark Jr from California who argues that the pipeline “is immoral, and wrong, and dangerous to us all. If we don’t stop it, who will?” he asks.

He is one of the co-founders of Veterans Stand For Standing Rock. The group’s online funding page, which has so far raised over $274,000, outlines:

“We are veterans of the United States Armed Forces, including the U.S. Army, United States Marine Corps, U.S. Navy, U.S. Air Force and U.S. Coast Guard and we are calling for our fellow veterans to assemble as a peaceful, unarmed militia at the Standing Rock Indian Reservation on Dec 4-7 and defend the water protectors from assault and intimidation at the hands of the militarized police force and DAPL security.”

The page continues: “It’s time to display that honor, courage, and commitment we claim to represent. It’s time for real Patriots. Now more than ever, it’s time for anyone and everyone to lead.”

“We’re not going out there to get in a fight with anyone,” Clark Jr. says. “They can feel free to beat us up, but we’re 100% nonviolence.”

Others will be joining too. Veteran Marine Jade Emilio Snell said: ‘I’ve been watching the news, how they’re spraying everybody and using rubber bullets, and these guys are fighting for what they believe in and as a veteran we took an oath. We’re not just there to protect Americans in foreign countries. We’re here to protect this country inside of it, too.”

Next weekend the veterans will join the Standing Rock Sioux tribe for a traditional healing ceremony. They will be dressed in military uniform and will then walk in a “massive line” for their “first encounter” with the “opposing forces.”

Clark said: “If we don’t stand up for the oppressed, that’s the snowball that starts that leads to everyone else’s oppression. It doesn’t matter if you are a libertarian, a conservative, or a progressive, this is everyone’s fight.”

Although Clark was originally hoping for 500 veterans to attend, some 1,400 have now registered on Facebook that they are going.

As the veterans prepare to mobilise, political pressure is growing on President Obama to sign an executive order that cancels the pipeline.

One peitition states: “We call on the President to instruct the Army Corps of Engineers to no longer ‘wait and see’ when they need to determine an ‘appropriate response’ to Dakota Access drilling under the Missouri River without an easement permit, which they are.”