The pipeline failed by a small margin. It could have bee3n larger if some democrats had not been bought out. I can't prove that that is the reason but why else? The vote:
Senate Democrats, by a single vote, stopped legislation that would have approved construction of the Keystone XL pipeline, one of the most fractious and expensive environmental battles of the Obama presidency.
And here's one democratic senator we don't need:
The political fallout, though, affected Ms. Landrieu more than the president, at least in the near term. She was able to persuade 14 Democrats to join all 45 Republicans to support the pipeline, but 40 Democrats and Senator Angus King, independent of Maine, combined to stop the legislation.