I was in D.C. Tuesday walking toward the National Mall when I saw a group of Native Americans on horseback. Other people were milling around, Native Americans and Anglos, talking among themselves and to members of the press. I was at the staging area for a march of the Cowboy And Indian Alliance which had just arrived in D.C., mainly from Nebraska but also from South Dakota and Montana, to oppose the Keystone XL pipeline.

I talked with Robin LaBeau (Indian name: Tataaka Agli Win), a Lakota council member of the Cheyenne River Sioux tribe, about her objections to the pipeline. "Do you see what's on the back of those young guys' shirts?" LaBeau asked me. "It says Unci Maka Defenders. Unci means grandmother, and Maka means earth. Grandmother Earth, we will stand to defend you. We wouldn't feel right if they continued to rape our grandmother. Those are strong statements, but that's the truth. You're burrowing down and you're hydro-fracking, and then you have nowheres to dump it so you're going to dump it someplace that's gonna leak. You're just tearing her up and spitting all over her and spilling all over her, and she's tired. She's had enough. She says, humanity, when are you going to wake up and start taking care of me, when are you going to start defending me? Why should we stand here to let the biggest dirty oil, the Koch Brothers come and destroy it?"

LaBeau (center in the photo above) told me the tribe had been assured the Keystone pipeline isn't going to run through any tribal land. "But it's going to plow right through some sacred trust lands," she said. "They want to burrow 60 feet under our Cheyenne River, our only water source."

The events in D.C. are organized under the banner, Reject and Protect. The protest began Tuesday at the event I attended and will culminate on Saturday with a demonstration where they hope to get thousands of people to urge President Obama to reject the pipeline. In between, there will be a number of events along with meetings with federal agencies and allied groups, and a prayer and song gathering in front of Secretary of State John Kerry's house.

The Cowboy And Indian Alliance was formed because people realized they shared a common concern about the pipeline running through their land and their efforts against the pipeline would be more effective if they worked together.

"Getting together with the ranchers is basically history happening here," La Beau said. "We're coming together as a group of humans worried about their future. 'Mni Wiconi' means 'Water is life.' All people need water. We're not talking about who's a Democrat and who's a Republican, we're talking about who wants a glass of clean water."

I spoke with Anglo ranchers and farmers from Nebraska who echoed LaBeau's concerns. They told me the proposed path of the pipeline cuts through their land and runs under the river. They know about past pipeline spills and understand that a spill in their area would destroy their lands and their livelihoods. When I asked them if this Cowboy-Indian Alliance was unusual, they assured me it was. They expressed a deep sense of satisfaction that they were working together with a group of people they had kept at a distance.

The march began with a prayer by the tribal members at the reflecting pool in front of the Capitol, after which a number of the ranchers and farmers stepped forward individually to give ceremonial gifts to an Indian elder, as a sign of respect and a statement of their common purpose.

Then the group marched to an area in the center of the Mall where a circle of tepees had been set up. In the afternoon, the group planned to put up another tepee which would be built by tribal members, with all the materials handed to them by the Nebraska farmers and ranchers.