A new article in Nature highlights a supposed rift among some scientists over Keystone XL: Is it a smart focus for climate activists or a distracting sideshow?
There doesn't seem to be nearly as much of a rift as author Jeff Tollefson suggests, but he does talk to some scientists who are conflicted over the Keystone focus:
The issue has ... divided the scientific community. Many climate and energy researchers have lined up with environmentalists to oppose what is by all accounts a dirty source of petroleum: emissions from extracting and burning tar-sands oil in the United States are 14–20% higher than the country's average oil emissions. But other researchers say that the Keystone controversy is diverting attention from issues that would have much greater impact on greenhouse-gas emissions, such as the use of coal.