Time’s Michael Grunwald: ‘Keystone isn’t the best fight to have over fossil fuels, but it’s the fight we’re having. Now is the time to choose sides. It’s always easy to quibble with the politics of radical protest: Did ACT UP need to be so obnoxious? Didn’t the tax-evasion optics of the Boston Tea Party muddle the anti-imperial message? But if we’re in a war to stop global warming–a war TIME declared on a green-bordered cover five years ago–then we need to fight it on the beaches, the landing zones and the carbon-spewing tar sands of Alberta. If we’re serious about reducing atmospheric carbon below 350 parts per million, we need to start leaving some carbon in the ground.’