[_delirium]

The tribes' position, at least (not necessarily the position of everyone else opposing it) is that it should be rerouted so it isn't tunneled directly under Lake Oahe, their main water source. That's not inconsistent with completing it, since tunneling under the lake isn't the only possible route. Though the pipeline owner would prefer not to reroute it.

That was also the basis for the Army Corps of Engineers ordering a more extensive environmental review. My understanding is the review wasn't to determine whether the pipeline would be built at all (that question isn't even in their jurisdiction), but 1) to evaluate whether the proposed route under Lake Oahe, which requires an easement to be granted beneath a reservoir they're responsible for, is a suitable option, and 2) if yes, to determine whether conditions should be placed on the easement to minimize the likelihood and/or impact of a spill. Their press release at the time is here: http://www.usace.army.mil/Media/News-Releases/News-Release-A...

[masonic]

  That was also the basis for the Army Corps of Engineers ordering a more extensive environmental review. 

No, that was a purely political decision that gave absolutely no indication of specific deficiencies in the original EIR, nor did it spell out any specific requirements for a "new" EIR.