America has the potential of increasing it's GDP, lowering unemployment by exporting oil that we don't use. Since our refineries are made to process heavier crude, the oil we produce due to fracking and horizontal drilling are not of that use in this country. Furthermore, enabling oil exports would create more employment and make our recovery even stronger.
Finally, if the U.S is allowed to export more WTI to the global market, this in turn will create more leverage for American "soft power". This strategy would also enable the emerging economies to rely on a steady supplier, thus speeding their growth rate.