The fact is that there is no way any politician can justify Keystone and still say it’s time to take stronger action on global warming. As Bill McKibbon’s 350.org puts it: “President Obama says that he will reject the pipeline if it poses a risk to the climate. That makes his decision simple: building an 800,000 barrel-per-day pipeline of the world’s dirtiest oil will mean more tar sands dug up and burned, and more carbon pollution.”