This issue has been basically decided (for now)
After Columbia the US was faced with the decision to continue human spaceflight or not. The decision was it would continue. A lot of input was taken from experts and members of Congress on what the space program needed to do. We now have Mike Griffin doing it. I am very impressed with the space architecture NASA has designed. It is a well thought out solution temporally, financially, politically and technologically. (Read:It wil be in place quickly, it's relatively inexpensive, it retains jobs across the country, and it will actually work!)