Prentice says the pipeline is ultimately in the best interests of both Canada and the United States, and says he believes that view will ultimately prevail.
He says North America is an integrated energy market and that without a pipeline, Canadian oil will continue to enter the U.S. by rail.
Prentice made the comments after U.S. President Barack Obama made good on a threat to veto a bill to approve the pipeline.
A White House spokesman says the veto doesn't necessarily mean Barack is against the pipeline, but rather to emphasize the decision is his alone given that the project crosses the border.
There's an expectation that U.S. lawmakers might try bringing Keystone back as part of bill that is favoured by Obama.
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