I couldn’t find a map that included both the Keystone XL proposed route and the Rosebud Sioux reservation lands, so I whipped up a shitty overlay:

As you can see the proposed route doesn’t actually go through the current reservation itself, but it’s going to be difficult for the project to avoid the myriad number of Tribal Trust lands external to the RIR.

So the questions for the Keystone backers are this:

1.) Do they plan on crossing any of the tribal trust lands?
2.) If not do they have the backing of enough non tribal land owners to snake a pipeline around the trust lands and through that stretch of South Dakota.
3.) I understand that many non-tribal ranch land owners are equally opposed to the pipeline project, if surface rights to the necessary lands cannot be purchased does the project then depend on the government employing imminent domain?

I’m not sure if tribal trust lands are considered part of the Sovereign Territory of the Tribe itself. My guess would be no, since they aren’t part of the actual reservation itself. However the pipeline will absolutely cross territory that was originally part of the 1910 Reservation border, and through lands that were subsequently taken away from the tribe, so the question of the status of the trust lands is germane. In any event it would be a PR disaster to force the pipeline onto those lands.

So that leave the only plausible route through the territory dependent on private land owners, who have also voiced their opposition. A pipeline isn’t a matter of mineral rights, its placement and transit through those lands is a surface rights matter, meaning that the proper easements will either have to be purchased for the entire route or the land will simply have to be taken by the government and repurposed for another private use. Something that would tend to violate a whole host of conservative principles regarding property rights.

I dont’ think that the Keystone debate is even about the pipeline anymore. It’s become a shibboleth and political war totem. The actual, significant practical issues the project faces aren’t even being discussed anymore.