The Obama administration has announced that they are delaying their decision on the Keystone XL pipeline until after the 2012 election.
For one thing, it is possible that Obama will get re-elected and then decide to approve the pipeline. Right now, he is worried about maintaining the support of his electoral base going into the presidential contest. After the election, he will never have to run again. Crucially, his own party will not be so worried about angering environmentalists. Right now, it is just possible that Democratic strategists are more scared of angry environmentalists than they are of Republicans. After the election, that will not be true and we are likely to see more of the same sort of compromises that have kept Guantanamo Bay open and prevented carbon pricing legislation from passing.
Of course, it is also possible that Obama will lose the election and be replaced by a Republican who is keen on digging up and importing as much as possible from the oil sands. It seems to me that having the Obama administration say no to the pipeline before the election would be preferable to them simply putting off the decision.
Even if Keystone XL is now dead, there is still more work to do. The next step is to block the Enbridge Northern Gateway Pipeline, which will seek to transport crude oil from the oil sands to the west coast of Canada. There are also plans to export oil sands crude by rail and to expand the Kinder Morgan TMX pipeline.