If we're in a war to stop global warming, then we need to fight it on the beaches, the landing zones, and the carbon-spewing tar sands of Alberta.

Richard Clement/ REUTERS Demonstrators carry a replica of a pipeline during a march against the Keystone XL pipeline in Washington, February 17, 2013.

The activists fighting the Keystone XL pipeline are radical-and right

The respectable center has recognized that climate change is not only real and man-made but also a genuine emergency. The scientific evidence has become too stark to indulge denial or dithering. The earth is hotter; Arctic ice is melting at a terrifying rate; staid institutions like reinsurers and the CIA are sounding dire warnings about rising seas and extreme droughts. There’s an emerging consensus that fossil fuel apologists are on the wrong side of the battle of the century.

But there’s also an emerging consensus-among newspaper editorial boards, respectable-centrist pundits, even the magazine Nature- that the rabble-rousing activists who have tied themselves to the White House gate and clamored for President Obama to reject the Keystone XL pipeline are picking the wrong fight. Stopping Keystone, these critics point out, wouldn’t prevent catastrophic warming. It might not even prevent the extraction from Canada’s dirty tar sands. It wouldn’t cut emissions as much as new coal regulations or clean-energy subsidies or carbon pricing. Meanwhile, approving the pipeline would create jobs and reduce our dependence on petro-dictators while signaling that Obama isn’t as radical as the tree huggers protesting outside his house.

TIME Graphic

Well, I’m with the tree huggers. The pipeline isn’t the worst threat to the climate, but it’s a threat. 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.

Yes, Keystone would create temporary construction jobs, but so would any other construction project. We’re already less reliant on Middle Eastern oil than we’ve been in decades. And there is zero chance that approving the pipeline would, as Nature suggested, help Obama “bolster his credibility” with industry groups and Republicans; they would celebrate their victory and continue their twilight struggle.

It’s true that imposing tough new carbon restrictions for power plants would do far more to control greenhouse gases than rejecting the pipeline, but there’s no reason Obama can’t do both. It’s also true that a tax or other government price on carbon could do even more to keep fossil fuels underground, but Congress simply won’t go there. Rejecting Keystone would at least put a logistical price on carbon from the tar sands, forcing industry to find costlier routes to market—while giving activists a chance to block those too.

What we really need is a political price on carbon, a policy presumption that cleaner is better. Fossil fuel interests understandably reject that notion. But so do respectable pundits, because they’re desperate to differentiate themselves from the unkempt riffraff who never shut up about the broiling of the planet. Respectable pundits see themselves as rational analysts, not emotional activists. They recognize the emergency but feel uncomfortable about the sirens. They endorse the war, but like armchair McClellans, they are always finding excuses for why we shouldn’t fight.

I’m an analyst too. I’m reasonably kempt. I’ve mocked the activists who whine about Obama’s “climate silence” while ignoring his climate actions— like unprecedented efficiency mandates that have slashed demand for dirty energy and unprecedented green investments that have launched a clean-energy revolution. But when it comes to Keystone, my analysis is that the activists are right. Fossil fuels are broiling the planet. The pipeline would turn up the heat. If Obama approves it, he’ll deserve all the abuse the activists hurl his way. There are many climate problems a President can’t solve, but Keystone isn’t one of them. It’s a choice between Big Oil and a more sustainable planet. The right answer isn’t always somewhere in the middle.

At his second Inaugural, after his memorable line about Selma and Stonewall, Obama finally broke his climate silence. He vowed to fight to slash emissions, “knowing that the failure to do so would betray our children and future generations.” Keystone isn’t a perfect battlefield, but neither was Selma or Stonewall. In a war, you don’t always get to choose where to fight. You still have to show you’re willing to fight.