THE CASE FOR ultimately approving the Keystone XL pipeline — always strong — has grown stronger.
A key environmentalist argument against Keystone XL has been that the project would encourage the extraction of bitumen, a particularly dirty oil-like substance, from the “oil sands” in Alberta. If activists could “shut in” Canadian bitumen, limiting the ability of oil companies to sell the product, they argued, perhaps petroleum firms wouldn’t be able to fully develop the oil sands.





