An argument that I've heard is it would cost ten times more for us to dislodge someone else from dominance of Space versus getting in there first and forcing others to dislodge us. In the context of the Cold War this sort of argument made a certain amount of sense. Are the Chinese a sufficient source of worry that we need to play this game with them? Probably not now but maybe 10 years from now.

The Persian Gulf and Iraq wars provided clear demonstrations of the importance of technological advantage in combat. Does the importance of this advantage extend into Low Earth Orbit? I don't know. However I do know the U.S. is spending a lot of money on classified aerospace related stuff. I'm convinced the main reason why NASA is still afloat is to attract young people into aerospace (the actual planetary science is almost an irrelevant after thought). It amuses me to read how manned space exploration is such a waste of money and we should focus exclusively on unmanned exploration. Anyone arguing that does not have a glimmer of a clue about what actually drives funding for Space Exploration.

Gary