AP Photo/Anja Niedringhaus

The State Department has released its environmental review of the proposed Keystone XL pipeline, concluding that building it would not much change climate emissions one way or the other, because if the pipeline were blocked, the oil would just be transported by rail or other smaller pipelines. This led top Dem donor Tom Steyer to write a letter to John Kerry arguing against the analysis and urging rejection of Keystone.

The State report was a blow for the climate movement, but not in the sense that is commonly understood. Indeed, Even if Keystone ultimately gets approved, the battle waged by anti-Keystone activists could very well contribute to a much more substantial victory later.

Here’s why. Keystone has always been largely a symbolic fight over a much larger goal, not an end in itself. By building up the pressure and attention on climate change, anti-Keystone forces — including Bill McKibben — have helped create the political environment necessary for strong action on climate change.

Some have looked at the State Department report and concluded that the leaders of the anti-Keystone movement are misleading rank and file environmental activists. As Jonathan Chait puts it in a piece accepting the State finding:

…the intuitive idea is for a movement to organize around the issues that matter, not the issues that are easiest to explain. Building a movement by misleading people is a strange choice.

Two points. First, this is a political document, not a scientific paper. That’s not to say that State has juked the stats, just that this sort of analysis — performed at a high level in the administration, under fierce scrutiny — is always necessarily affected by the broader political context. “The oil will be shipped anyway,” relies on many contestable political assumptions about other projects and the price of oil. They may well be correct, but let’s not mistake them for measurements of the Earth’s circumference.

Second, many have accepted at face value — as Chait does — the idea that transport will be quickly and efficiently shunted from Keystone to elsewhere. But turn the reasoning on its head: if Keystone XL will do exactly nothing for total oil production, why are we building it in the first place? The answer, of course, is that oil transport is a damnable, high-friction business vulnerable to disruption. United States rail and pipeline infrastructure sucks, and oil companies tend to skimp on maintenance; last year featured multiple pipeline spills and six separate oil train derailments in the U.S. and Canada, which created terrible press and delays in new infrastructure. This isn’t like the market for iOS apps.

Chait could be right that stopping Keystone would be ultimately pointless. But even after looking over State’s reasoning, I think it’s at least equally plausible (in line with this EPA analysis) to believe that blocking Keystone will reduce carbon emissions on the margin, in addition to future spills avoided and whatnot.

Now, it is true that fighting individual pipelines one by one is a pretty dumb strategy if one’s goal is stopping climate change by that method alone. Oil companies will always win in the end at that game. Of course, that has never ever been the long-term strategy for Bill McKibben (who knows all about EPA regulations, even mentioning them before Keystone in this piece) and the other Keystone activists. The point is to use Keystone as a coordination point to create political pressure on the administration to take more drastic action. In that, they’ve already succeeded.

This is similar in some ways to the Occupy Wall Street protests. They were crazily diffuse — they had no laundry list on jobs or inequality, but they managed to get Congress talking about unemployment, at least for a minute. The Tea Party protests in 2009 were basically incoherent, but they fueled a political reaction as strong as any in recent history. Mass movements are almost never precisely calibrated in policy wonk terms. But that doesn’t stop them from massively influencing the course of political debate.

What this means in concrete terms is that it is highly possible for the administration to approve Keystone and for McKibben and company to win an enormous victory. As I’ve written, the EPA is already using its authority to regulate pollution to shut down dozens of coal-fired power plants across the nation. If they come out with a strong new rule regulating carbon pollution on existing coal-fired plants, that will have an effect on carbon pollution thousands of times greater than Keystone. If that happens McKibben will deserve substantial credit.

I would say Keystone is still worth stopping, because climate change is such an enormous threat that anything with even a small chance of cutting emissions is worth a shot. But even if the activists lose the battle on the pipeline, they could still win a grand victory later.