0bama may be using Buffet as a way to not make the decision on the pipeline. If he approves it the enviros are ticked but with transporting by rail and trucks it keeps the enviros and unions somewhat satisfied.
I have no doubt that 0bama is using Buffet and he will throw him under his own train when and if circumstances make it advantageous to The Won. For now I think Sen. Hoeven is engaging in wishful thinking. Jugears held fast on this through the 2012 elections so I don’t think he has any reason to cave now. Flaming rail cars notwithstanding.