President Barack Obama reportedly told House Republicans on Wednesday that liberals have exaggerated by warning that the proposed Keystone XL pipeline would cause environmental devastation. Obama also said the purported jobs and energy benefits were exaggerated too. But the former comment is more significant. In all likelihood, if the president doesn't believe he has a clear reason for using government to scuttle a business decision, he won't.

For the last two years, climate activists have made blocking Keystone their top priority. A loss at the president's desk would badly sting. But the climate movement shouldn't judge its strategic decision to prioritize Keystone based on the final decision of one man. The judgment should be based on whether the Keystone campaign helped strengthen the climate movement and feed a sense of urgency for climate action among the public.

Sadly, on that score, the Keystone campaign already has been a failure.

Granted, climate activists have done a lot of things right. Getting arrested at the White House in August 2011 gave this once-obscure issue a jolt of media attention and focused the broader environmental movement. Subsequent political pressure through the summer and fall arguably prompted President Obama to postpone the decision on whether to approve the pipeline.

But that only proved climate activists can make a Democratic president dance before an election. And remember, the roadblock to legislation that would permanently cap carbon is not the White House. It's Congress. Specifically, Democrats from coal and oil states, and Republicans from every state.

To make reluctant congressmen budge would require a much bigger display of strength than a few staged arrests.

Last month's "Forward on Climate rally" — which followed another round of White House arrests, this time including the president of the Sierra Club — was supposed to show that strength. But the overall turnout of about 40,000 was relatively paltry compared with the estimated 200,000 that rallied in Washington for gay equality in 2009 and immigration reform in 2010. One prominent attendee, Tom Englehardt of, lamented on the Huffington Post, "Where is everybody?"

Keystone has failed to stoke that sense of urgency, despite environmentalists' claims that its approval meant "game over" for the climate. In fact, climate activists haven't even succeeded in convincing the public there's a connection between Keystone and the climate.

While a clear majority supports government regulations to prevent global warming — a February Pew poll found 62 percent support limits on carbon emissions from power plants — a whopping 70 percent support Keystone, according to a March Fox News poll. (Yes, the Fox poll uses slanted wording, but it's not all that different than the 59 percent support measured by a more neutral Washington Post poll last June.)

Why hasn't Keystone been enough to spark a bigger climate movement? Two main reasons:

1. Keystone shrinks the climate coalition

While the 2010 legislative effort to enact carbon cap legislation fell short, legislators still put together the broadest coalition ever to back a climate bill. Heavy emphasis was put on creating green jobs and helping corporations gradually adjust to limiting emissions. Tough compromises were made. In turn, the bill that cleared the Democratic House in 2009 boasted support from utilities, agribusiness, manufacturers, and labor. When that wasn't enough to get coal-state and oil-state senators on board, a bipartisan trio of senators offered more concessions and drafted a new climate bill that, for first time ever, received the backing of some oil companies. Then, right before Senate negotiators were about to roll out their coalition, BP's Deepwater Horizon blew up. The push to clamp down on underwater drilling broke the coalition apart. The bill never saw the light of day.

Climate activists have taken the wrong lesson from this legislative failure. Instead of seeking to put a broad coalition back together, they have retrenched in hopes of rebuilding a bottom-up movement. By focusing on killing a pipeline construction project, not only have corporations dropped out, but so has labor. Neither has any stake in the fight.

Stripping down the movement to the most dedicated climate activists hasn't helped show coal-state and oil-state politicians, who are needed to pass any legislation, that the climate movement is big enough to fear. And losing corporate and labor ambassadors hasn't helped to intensify the urgency.

2. Keystone doesn't simplify the debate

Environmental leaders hoping to prioritize Keystone argued that it amounted to a last stand. A pipeline that allowed the Canadian tar sands to be tapped meant "game over" for the climate. No complicated explanations of what "cap and trade" means. No uncomfortable compromises with corporate interests. Just a simple line drawn. Pick a side and take a stand. But when you make an absolute claim, it's bound to get tested. When the draft State Department environmental review study released this month didn't back up the dire claims, movement leaders were put on the defensive, attacking the industry ties of the authors and the quality of the analysis. Even if they have a point, they're stuck in a he said-she said with a seemingly credible source, which is not conducive to simplifying the case.

Furthermore, other reports published prior to the State Department study similarly found that while tapping the tar sands is not good for the climate, the impact would fall short of "game over." Even movement leaders have been forced to concede the point when pressed. In fact, a Bloomberg Businessweek story reported that some environmental organizations involved with the campaign didn't quite share the "game over" view:

Some more mainstream environmental groups, those that specialize in policy as opposed to public protest, quietly say the power plant [emissions] issue is more important than Keystone, though they are reluctant to publicly part ways with [Keystone protest leader Bill] McKibben. "Symbols are important," says Sierra Club President Allison Chin. [Businessweek]

Symbols are important, but they have to be symbols that effectively crystallize the issue. Keystone didn't cut it.

None of this is to say that the Keystone pipeline is a good idea. There are certainly legitimate reasons to oppose it. And there's nothing wrong with different organizations employing a range of actions, from the confrontational to the conciliatory, to reach as many audiences as possible. There's no need for the pragmatists to push false choices on the idealists.

The problem is that the environmental movement has overcompensated for the heartbreak of 2010, gone all in on Keystone, and let critical outreach to business and labor wither. There's no getting around the fact that the endgame involves convincing right-leaning Democrats and some Republicans to pass climate legislation. It would take an extremely long time to build a movement within the coal states and oil states that would stand a chance of prying politicians away from their corporate donors and negating the need for hard compromises. And as any climate activist can tell you, the climate can't wait.