President Obama will meet today with Canadian Prime Minister Stephen Harper and the subject of the Keystone XL pipeline, still under consideration for approval by the State Department, will almost certainly be a topic of conversation. The Keystone XL pipeline would carry highly polluting Canadian tar sands crude oil from Alberta, Canada all the way to refineries on the Gulf Coast. Environmental groups argue that the pipeline is unnecessary and a threat to ecosystems in the wake of the million gallon oil spill here in Michigan last July