spend a whole stack of money that the US budget cannot afford? That is no incentive. If you cannot afford it, then you don't spend it. it's simple economics even if bush and co cannot understand it.
You know most liberals like yourself believe that we spend ourselves out from a recession/depression/stagnation like Roosevelt did during the 30s.
Think of all the jobs it would create and all the material gains from a lunar base. Mining of the moon, colonization, travel to and back.
See the article below when youre not drunk. It describes what helium 3 is used for and how it can be hugely beneficial to the world.