Canada is the largest supplier of oil to the U.S., supplying more than 2 million barrels of oil imports a day. Here the heads of the U.S. and Canadian Chambers of Commerce argue that a new pipeline from Alberta, Canada to Texas would supply an additional 1.1 million barrels of oil a day. The pipeline project- called the Keystone XL pipeline- has been under review by the U.S. government since 2008. An Energy Dept study in February 2011 found that the project should go ahead, but it is being held up for further environmental studies by the Obama administration. The delays may be the result of opposition to Canadian oil sands development. At the same time significant progress has been made in reducing the environmental impact of oil sands development. About 80% of the water used in the process is now being recycled. Tailing ponds containing waste product from the oil shale process are also being reclaimed for green land and replanted with trees and shrubs. TransCanada says the Keystone XL pipeline could create 20,000 new American jobs for construction, and 250,000 jobs in the long run. Strict environmental standards can be followed say Donahue and Beatty, because the U.S. is partnering with Canada....