Another idea, is after the ISS station is done, perhaps we could do a similiar thing with a moonbase. With the U.S. taking the lead, and other nations taking supportive roles. That would be less costly then doing it ourselves. For example, if India, and Japan went in with us, it would help them improve their programs, and we might be able to do it faster.
Continuing on that idea if India and Japan were to help us on our next generation spacecraft, it might get the next generation spacecraft ready sooner at less expense. For example, if they loaned us some engineers or perhaps some monetary contribution to do help with the development. They could get access to plans and other things from us.