There were two questions. First, what has federal recognition afforded the Standing Rock Sioux as it relates to the Dakota Access Pipeline; the answer is it afforded them the opportunity to sue the Army Corps of Engineers (which is one of he federal agencies responsible for permitting the pipeline) for not consulting with the tribe. The tribe is entitled to consultation because of their status as a federally recognized indigenous government. 

The second question was whether that has stopped the pipeline. The answer is at this time, yes, it has. Under the Obama administration, his Dept. of Justice has declared that the Army Corps will not be allowing further construction along the areas in its jurisdiction.

TBH the biggest "chance" we take is if we don't explore federal recognition. It provides us with the opportunity to speak for ourselves, to directly negotiate with the Feds, and to protect our programs and resources. Hope that answers your question.