Excerpt: The New York Times NEAR CANNON BALL, N.D. — When visitors turn off a narrow North Dakota highway and drive into the Sacred Stone Camp, where thousands have come to protest an oil pipeline, they thread through an arcade of flags whipping in the wind. Each represents one of the 280 Native American tribes that have flocked here in what activists are calling the … [Read more...] about From 280 Tribes, a Protest on the Plains