I believe they want the pipeline to the east to solve the oil sands discount problem.

http://www2.canada.com/story.html?id=6292444

CALGARY - Oil producers in Alberta are giving up $18 billion a year by selling barrels of Canadian oil priced substantially lower than international crudes and the losses are poised to continue into 2014, CIBC World Markets said Monday.

The warning comes as analysts say strong volumes out of the Bakken oil play in North Dakota and rising oilsands production in Alberta are competing for access to U.S. refiners and markets.

The resulting congestion on existing pipelines has put Alberta crude at a disadvantage, with $30-per-barrel discounts to benchmark West Texas Intermediate expected to be more the norm than the exception.