Friends of Big Oil have been making a habit in this session of Congress of holding essential legislation hostage in order to hasten construction of the dangerous Keystone XL tar sands oil pipeline. It's happening again now as Congress takes one more stab at passing a bipartisan transportation bill -- a critical piece of infrastructure legislation that is important to our future economic growth and is conservatively estimated to create one million jobs. Keystone XL is fraught with flaws, from the destruction of pristine boreal forest ecosystems, to the potential leaks into the Ogallala aquifer along its route. This measure is a poison pill, a gift to Big Oil that threatens the transportation bill and could hold up road and transit projects and squash much needed jobs. Instead of encouraging the production of one of the dirtiest, most polluting fuels and sending it through America's heartland, Congress should be promoting clean energy solutions. Keystone XL is a devious dagger in the transportation bill and will not bring us closer to energy self-sufficiency, but further line the already bulging pockets of Big Oil.