The Lakota people who watched the surveying parties and eventually the soldiers moving into the Powder River Country in 1866 understood this perfectly well, even if they would not have used the word “sovereignty” or the framework of American political theory to describe what they knew.

They had seen what had happened to other peoples who had allowed roads through their territory, watched the settlement patterns that followed, and observed how quickly the presence of American civilians and military infrastructure changed the political facts on the ground.

The Bozeman Trail that began operating in the early 1860s started at the North Platte River crossing at Fort Laramie and ran northwest through the Powder River Country before swinging west toward the Montana goldfields.

It was roughly 400 miles of difficult country — the Big Horn Mountains created a significant obstacle that required passes at altitude, and the river crossings required skill and the right conditions.