Many in the environmental movement have taken the position that building Keystone — and thus allowing for increased production of tar sands oil — would be ruinous for the planet. Not only would it further the world’s dependence on fossil fuels, but, if it enabled the full exploitation of the tar sands, it would emit so much carbon that it would be “game over” for the planet, in the memorable words of James Hansen, an anti-Keystone scientist. As I’ve written before, these claims are wildly overstated; indeed, the Canadian government likes to note that, in 2012, eight states, starting with Texas, had higher emissions from their coal-fired power plants than Canada did from its oil sands. And transporting oil by train, as is currently being done, is far more dangerous than sending it through a state-of-the-art pipeline.

At the same time, the Republicans who want to use Obama’s veto as a symbol that he is willing to forego good jobs to please his environmental supporters are equally wrongheaded. Most of the American jobs related to Keystone would involve building the pipeline. Once it was up and running, the number of new jobs it would create would be minimal.

There is a third entity for whom Keystone has become a symbol: the conservative government of Stephen Harper, the Canadian prime minister, which has pushed for approval of the pipeline by the United States with an urgency that has sometimes felt a little desperate. In 2011, Harper said that approval of the pipeline should be a “no brainer” for the U.S. Canadian officials have threatened that if the U.S. doesn’t approve the pipeline, the oil would likely go to China instead. And it has treated Obama’s reluctance to make a decision on the pipeline as a reflection of American-Canadian relations, rather than what it is: an issue of American politics. There are many Canadians who believe that the Harper government has badly mishandled the Keystone issue.

At the same time, Harper’s government has not exactly been leading the climate change charge. His administration pulled Canada out of the Kyoto Protocols, the landmark 1997 agreement that committed countries that signed on to mandatory emissions reductions. “We are known around the world as being climate change obstructionists,” said Peter McKenna, a political scientist at the University of Prince Edward Island. “Harper always equates getting serious about climate change as having a negative effect on the Canadian economy.”

It is this state of affairs that Bloomberg seeks to exploit. Late last year, the Obama administration announced a climate change agreement with China, which commits both parties to lowering their greenhouse gas emissions. Because Harper so badly wants the Keystone pipeline to be approved, the U.S. government has tremendous leverage, says Bloomberg, to cut the same kind of deal with Canada. After which, the president could approve the Keystone XL oil pipeline with a clear conscience, knowing that he had mitigated the worst of its effects on the planet.