Canadian Prime Minister Steven Harper sent President Obama a letter in August that all but begged him to OK the Keystone XL pipeline project.

Citing high-level sources, the Canadian Broadcasting Corp. reported that the letter indicates "the prime minister is willing to accept targets proposed by the United States for reducing the climate-changing emissions and is prepared to work in concert with Obama to provide whatever political cover he needs to approve the project."

Obama has yet to respond to the letter.

The $7 billion project would build a pipeline from Canada south through the plains states to the Gulf of Mexico. While privately funded, it requires the approval of both governments.

Harper has been seeking Obama's approval for years, but the president has only delayed the decision. The earliest a decision could come now would be sometime in 2014.

Obama initially appeared willing to approve the project in 2011, but pulled back after Big Green environmental groups made opposing it a litmus test for the 2012 campaign. They warned Democrats that they could lose campaign funding and votes.

The president has not definitively ruled it out, though, holding out hope to the project's supporters that some kind of deal is still possible.

In a June environmental address at Georgetown University, Obama appeared to create wiggle room when he said he would approve it if the "net effects" do "not significantly exacerbate" pollution.

Recent studies have indicated that that would be the case.

In a July New York Times interview, Obama dismissed the findings of his own State Department that the project would create more than 42,000 jobs during its construction.

Indeed, the CBC report notes: "Obama hasn't said what he wants, or needs, to assuage environmentalists that Keystone XL is in America's national interest, or to convince congressional Democrats facing re-election next year that it can be approved without sabotaging their campaigns."