Scientific American: The U.S. Senate voted 62 to 36 yesterday to build the controversial Keystone XL Pipeline that would bring oil from tar sands in Canada down through the U.S. Tar sands are one of the dirtiest forms of oil and expansion of their use would ensure too much carbon dioxide in the atmosphere, helping climate change wreak even more havoc. Yet this prospect is exactly what many of the same Senators who approved the pipeline voted to avoid, philosophically at least, just last week. How can that be? And who...