Writing at Time Magazine's Swamp Land Blog, foreign policy expert Fareed Zakaria makes his argument for why the U.S. should sign off on building the Keystone XL pipeline.  

One way to think about the keystone project–the 2,000-mile (3,220 km) pipeline that would bring oil from the tar sands of Canada to the Gulf of Mexico–is to ask what would happen if it is never built. The U.S. Department of State released an extremely thorough report that tries to answer this question. It concludes, basically, that the oil derived from Canadian tar sands will be developed at about the same pace whether or not there is a pipeline to the U.S. In other words, stopping Keystone might make us feel good, but it wouldn’t really do anything about climate change.