Washington Post: When it comes to political hot potatoes, there may not be a better example than the Keystone XL oil pipeline. Since Canada-based TransCanada Corp. first proposed the pipeline in 2008, it has served as a litmus test for where President Obama stands on energy, economic and environmental issues. One of those latter issues is climate change, as environmental groups that oppose the pipeline argue that approving it would be bad news for the climate.
Whether the pipelines construction would significantly...