Keystone is at best a waste for America and at worst a natural disaster waiting to happen. It's a pipeline down to Mexican refineries so Canada can sell cheap tar sands oil to China. The problem is it's a _long_ pipe line, and they have a history of breaking and nobody noticing (since it costs lots of $$$ to monitor them) until after a community's ground water is heavily contaminated. If it happens in a mid sized town or city where it's too expensive to buy everyone out those people are just screwed.
The problem is these sorts of things are only a matter of time. With current tech maintenance costs more than allowing the disaster to happen. If the companies were severely punished for the spills that wouldn't be an issue. But if BP had to clean up their last mess they wouldn't exist as a company, and the owners would be broke. Those guys just buy off politicians until their in the clear. Heck, the CEO of TEP cried a little on Camera and got away with giving thousands of people cancer because he wouldn't pay to upgrade the safety on his factory. It was called a "Once in a 100 year event", but there were records showing it had been 100 years since the last one. That's some Mighty fine work there, Lou.
So to summarize my rant: You're asking me, as an American, to take a big risk that sooner or later is practically guaranteed to end in an etiological disaster in exchange for at best a few thousand jobs and a bit of cheap oil for China? I think
This just about sums up my feelings.