Everyone is trifaling about the budget and how much the SEI will cost and for the tangible as well as the intangible payback as others have said for the investment into such a bold plan. Rather then remebering that it is more about self pride as to have men once again exploring the moon and to maybe someday visit mars. We as a nation should have never stopped going to the moon but because there was no plan beyound one up-manship for the cold war we were bond to fail.
Look at this as not an expense but as a way to motivate NASA into finally thinking more like a business of which they must manage it's earnings rather than give me give me aproach to what they feel is what we want them to do.