. . . the law Bush passed prohibits the import of oil that has a higher carbon footprint than standard fuel.
"Tar sands oil is considered one of the “dirtiest” sources of petroleum on earth, loaded with so much carbon that the extraction and use of the Canadian resource could make it almost impossible to reverse the impact of global warming anytime soon, according to some scientists.
Tar sands oil was essentially outlawed for use in the U.S. when President Bush approved section 526 of the Energy Independence and National Security Act of 2007. Section 526 prohibits the government—the largest fuel purchaser in America—from using taxpayer dollars to purchase fuels that have a higher carbon footprint than conventional oil (namely, tar-sands petroleum)."
http://www.allgov.com/ViewNews/Tar_Sands_Oil_Pipeline_would_Violate_Bush_Era_Pollution_Law_110921also,
Keystone XL is an export pipeline.
According to presentations to investors, Gulf Coast refiners plan to refine the cheap Canadian crude supplied by the pipeline into diesel and other products for export to Europe and Latin America. Proceeds from these exports are earned tax-free. Much of the fuel refined from the pipeline’s heavy crude oil will never reach U.S. drivers’ tanks.
Reducing demand for oil is the best way to improve our energy security. U.S. demand for oil has been declining since 2007. New fuel-efficiency standards mean that this trend will continue once the economy gets back on track. In fact, the Energy Deptartment report on KeystoneXL found that decreasing demand through fuel efficiency is the only way to reduce mid-east oil imports with or without the pipeline.
http://www.tarsandsaction.org/spread-the-word/key-facts-keystone-xl/