Globe and Mail: Rejecting Keystone XL was not about Canada. It was about U.S. President Barack Obamas legacy and his credibility. The President has decided that global warming poses an existential threat. And so, for Mr. Obama to head to Paris next month seeking to save the planet after giving the go-ahead to an $8-billion pipeline that has come to symbolize Big Oil digging up some of the worlds most carbon-laden fossil fuel would have looked like hypocrisy. The Presidents ability to make the case to other...