We made this mistake in the moon race. Instead of building a Space Station first (as Von Braun suggested), then constructing exploration vehicles in space, we went with the other route and launched directly from Earth. We could have had Earth-orbit rendezvous of lunar and other exploration craft. After the Moon, we would have still had a foothold in space to continue to explore, and possibly colonize. Instead, we got some data, some nice pictures, some rocks, and memories.
IMHO, if we intend to have a presence elsewhere in our solar system, we should act like it. Establish and expand. A solid moon base would allow asteroid exploration for raw materials (manned or otherwise) and manufacturing in low g utilizing those materials, without EPA regs. That alone has merit.
The goal needs to be stated. Bush is the one who can give the order and the time frame. A lot of people are waiting to hear his mission outline.