Victories against climate change have been rare, so it’s vital to recognize them when they happen. The Obama administration’s decision to delay the Keystone XL pipeline is one such victory—arguably the most important achievement in the climate fight in North America in years.

True, the administration’s November 10 statements did not outright kill the 1,700-mile pipeline, which the TransCanada company wants to build to transport highly polluting tar sands from Alberta, Canada, to refineries on the Texas coast. Yes, President Obama or his successor could try to greenlight the project in 2013, when the State Department’s new review of the project is due. But that’s unlikely, as TransCanada’s CEO, Russ Girling, has acknowledged. The project’s contracts require the pipeline to be completed by 2013, or refineries will be free to look elsewhere for supply, which Girling expects they will.

In any case, such caveats mean only that the Keystone victory is not absolute. But when a $7 billion project involving the number-one US trading partner and oil supplier, a project that Secretary of State Hillary Clinton only a year ago said she was “inclined” to approve, is very publicly postponed—even as the inspector general of the State Department launches an investigation into cronyism involving a former top aide to Clinton—good luck putting that Humpty Dumpty together again.

The climax of the Keystone campaign came November 6, when some 12,000 activists surrounded the White House (evidently a first) to urge Obama to honor his 2008 campaign pledge to fight climate change. “We want jobs but not as gravediggers for the planet,” Roger Toussaint, head of Local 100 of the Transport Workers of America, told the crowd in one of the strongest green declarations by a US labor leader. (Unfortunately, other elements of organized labor did not play against stereotype; the Building Trades Unions went so far as to team up with the oil industry to launch a “Jobs for the 99” campaign, co-opting Occupy rhetoric for their pro-pipeline propaganda.)

The breadth of the anti-pipeline coalition—indigenous people, progressive labor unions, youth, faith, farmer, community and environmental activists—was just one way this crusade contrasted with previous environmental campaigns. Other key differences: demands were more concrete and more radical. Strategy was set more by grassroots activists than by Beltway insiders. Tactics stressed people power—putting feet on the street, going to jail—over policy papers. The message was comprehensible to ordinary people rather than off-putting. And thanks to the Occupy movement, journalists were primed to pay attention to street protests.

All these factors combined not only to deliver the immediate victory over Keystone but to reanimate a movement that had been reeling after the failure of the Copenhagen climate talks in 2009 and the defeat of climate legislation on Capitol Hill in 2010. “You need victories to build a movement, and how you win can be as important as what you win,” explained Steve Kretzmann, executive director of Oil Change International, an NGO that punctured the “energy independence” rationale for Keystone by revealing that the oil it transported to Texas would be sold on the world market, not reserved for American gas tanks. Kretzmann added, “For once a big battle coming out of the environmental community was not about an obscure policy proposal, like cap and trade. [The pipeline] was made into a moral issue about what we want the future of our country to be and what we’re willing to do about it. At the White House, I had one seasoned activist tell me, ‘I feel like I finally can crawl out of the fetal position I’ve been in since Copenhagen.’”

As with the Occupiers, establishment voices quickly registered their disapproval—and their political tone-deafness. Some, like Council on Foreign Relations fellow Michael Levi, even suggested that the delay would hurt the climate fight, because Bill McKibben and other climate organizers had muddied their message by taking advantage of the “not in my backyard” sentiments of Midwestern farmers who—oh the horror!—are Republicans. Such NIMBYism, Levi sniffed, could be used to undercut future deployment of wind farms and other clean energy sources.

The truth, as McKibben has said many times, is that he and his colleagues came to the Keystone party fairly late. “The indigenous peoples in Canada have been fighting this from the start, and then folks along the route” got active, McKibben told The Nation. “I joined in this spring, when [NASA scientist James] Hansen made clear the size of the [tar sands] carbon pool. Our role was to take a regional fight and make it national and international, which I think we managed to do.”

And not a moment too soon. One day before Obama’s announcement, the International Energy Agency released its annual report on the “World Energy Outlook.” The IEA is no den of subversives; it’s run by many of the world’s largest oil-consuming nations. Its report warns that without radical changes in the world’s energy infrastructure in the next five years, humans will make climate change irreversible. In this context the defeat of Keystone is exactly the kind of radical change, in infrastructure and activism, that’s needed.

Mark Hertsgaard