Sunday rally could tip balance against Keystone pipeline Opponents of the proposed Keystone XL pipeline claim "tens of thousands" will gather Sunday for what's billed as "the largest climate rally in American history." If organizers really can deliver that many people to decry efforts to build a pipeline to funnel Alberta oil sands crude - heavy with carbon blamed for climate change - to Gulf oil refineries, then the political balance could tip against Keystone. At stake, activists say, is not just another pipeline but holding President Barack Obama accountable - ensuring that deeds, not just words, make meaningful inroads in reducing greenhouse-gas emissions during his second term. Is the pipeline a tipping point in American priorities? On Sunday, the White House will be watching. Officials will not just be counting crowds assembled on the Mall and marching to within sight of the Oval Office, but also seeing whether the protest galvanizes national media coverage, unlike the arrest of a handful of activists last week that was largely ignored. "For the sake of our children and our future, we must do more to combat climate change," Mr. Obama said last week, adding: "We can choose to believe that Superstorm Sandy and the most severe drought in decades and the worst wildfires some states have ever seen were all just a freak coincidence, or we can choose to believe in the overwhelming judgment of science and act before it's too late." It was music to the ears of anti-Keystone forces determined that Mr. Obama match high-minded promises with action. "Rejecting the Keystone XL tar sands pipeline" is the first important step, says the National Resources Defense Council, arguing that "much of President Obama's legacy will rest squarely on his response, resolve and leadership in solving the climate crisis." In the United States, Keystone has achieved symbolic importance far exceeding the impact on either energy security or global warming that the crude it carries would deliver. As for Canada's export needs, they barely register on the political spectrum. Mr. Obama, clearly sensitive to the dynamite Keystone could trigger, deliberately delayed the decision until after he had secured a second term. That time has come. Is Keystone as key to Americans as it is to Canadians? For Canada - at least for the Harper government and the Canadian oil industry, especially those digging up the vast, carbon-laden heavy crude from the Alberta oil sands - Keystone is a critical piece of an ambitious development and export plan. The proposed pipeline would offer a route to market for 830,000 barrels a day, a vital outlet that would permit massive expansion of the current 1.6-million-barrels-a-day production. While Canadian pro-Keystone lobbying efforts in the United States have stressed that giving the project a green light would ensure American jobs and, more importantly, American energy security, the reality remains that, in the overall U.S. energy market, Keystone is much less important than it is to Canada. Still, the Canadian argument is that Mr. Obama can "do both," as Ambassador Gary Doer puts it: cut harmful emissions - a goal Canada shares, the Harper government increasingly stresses as doubts increase about Keystone - and secure U.S. energy supplies. "A majority of Americans would prefer Canadian oil to imports from Venezuela or the Middle East," Mr. Doer told The Globe and Mail, pointing to polls that strongly back that choice. Ask different questions, and another majority says climate change is a pressing problem and the President should act to cut carbon emissions. In this fierce debate, Keystone XL has become an icon. "It's awful hard to reconcile wanting to reduce greenhouse-gas emissions with [approving] the dirtiest oil project in the country," says Michael Brune, executive director, Sierra Club. The President gets this, he understands this challenge, and we're here to ensure his ambitions rise to the level of the challenge. Where do pipeline politics go next? Soon, likely within weeks, the revised environmental assessment required by the U.S. State Department - because the pipeline crosses an international boundary - will reach the desk of new Secretary of State John Kerry. But the real decision rests in the Oval Office. As often happens, it may not be a simple "yes" or "no." Nearly a year ago, when jobs easily trumped climate-change worries, at least in the run-up to an election, the President gave a resounding go-ahead to the southern, all-American leg of the project. "Break through the bureaucratic hurdles, and make this project a priority ... and get it done," Mr. Obama said then. The much tougher decision - to open a spigot on a massive inflow of Alberta oil sands crude - will come this spring. Some expect it to be linked to clean energy commitments. Perhaps, as Mr. Doer suggests, the President will "do both."