Even the Bush administration wouldn’t touch tar-sands oil
Even if the Obama administration approves the Keystone XL pipeline, Canadians won't be able to sell the carbon-intensive tar-sands oil to one very big energy consumer: the Obama administration. Back in 2007, the federal government, under the leadership of George W. Bush, passed a law that forbade it from buying oil that's dirtier than conventional oil. And tar-sands oil is.
The Canadian government has been trying for years to wiggle its way around that restriction. The U.S Chamber of Commerce has also tried to free the Department of Defense from its shackles. But as of right now, the federal government is not actually allowed to buy the oil that Keystone XL would bring in.
There are other American customers for the oil. But it certainly feels like a self-contradictory, nonsensical policy to decide tar-sands oil is bad enough for the country that the government shouldn't use it, then have the government open up the spigot.