When President Barack Obama weighed in on the Keystone XL pipeline controversy on Tuesday, his comments became a kind of Rorschach inkblot test for rival lobbies, reflecting their wishes for the fate of the long-delayed project.
The pipeline, designed to carry 830,000 barrels of crude oil per day from the Canadian oil sands and the Bakken shale in North Dakota and Montana south to Texas refineries, was first proposed in 2008, but approval has been delayed several times due to a groundswell of criticism.
For months, the White House has been loathe to comment on the pipeline, which is still wending its way through a State Department study process.
Environmental critics argue that extracting crude from the oil sands in Northern Alberta produces an excessive amount of carbon pollution. Obama's political critics - business groups and Republicans - have urged him to approve Keystone because of the oil and construction jobs the pipeline will bring.
On Tuesday, Obama laid down his standard for approving the project, a surprise inclusion in a wide-ranging speech at Georgetown University about his plan for limiting carbon emissions responsible for climate change.
"Our national interest will be served only if this project does not significantly exacerbate the problem of carbon pollution," he said.
"The net effects of the pipeline's impact on our climate will be absolutely critical to determining whether this project is allowed to go forward. It's relevant."
Both pipeline proponents and pipeline haters cheered his remarks - an unusual reaction.
Environmental groups, who are convinced the pipeline spells doom for the planet, were encouraged.
Tom Steyer, a billionaire former hedge fund investor and Democratic fundraiser who has backed a campaign to reject the pipeline, said Obama was "ringing the Keystone death knell."
Jim Murphy, senior counsel for National Wildlife Federation, called it "a huge step towards rejection of this pipeline."
However, backers of the project said the State Department had already determined the answer to Obama's question.
In its latest draft environmental impact statement released in March, the department said the pipeline would result in "no substantial change in global greenhouse gas emissions."
Joe Oliver, Canada's minister of natural resources said Obama's new comments "should lead to speedy approval" of the pipeline because of the State Department's conclusion.
Shawn Howard, a spokesman for TransCanada, the company that is building the pipeline, reiterated the argument that if it was not built, the oil would move to market by truck, rail and tanker, which would significantly add to global greenhouse gas emissions.
Despite Oliver's reference to the State Department report, it remains a draft subject to revision. The Environmental Protection Agency has said the State Department needs to take a second look at its analysis.
Obama's final decision is expected later this year or early in 2014.
Jason Bordoff, director of Columbia University's Center on Global Energy Policy, who until January was a top White House official on energy and climate change issues, said it was difficult to predict what the president would decide.
"I can understand why people might be unclear as to what to make of it - I'm not sure what to make of it," he said of Obama's remarks.
"So I can understand why people might view it through the lens of their own take on the pipeline."