Thus, the central objection raised against the human settlement and terraforming of Mars: Such projects may be technologically feasible, but there is… - Robert Zubrin

Currently we see around us an ever more apparent loss of vigor of our society: increasing fixity of the power structure and bureaucratization of all levels of life; impotence of political institutions to carry off great projects; the proliferation of regulations affecting all aspects of public, private, and commercial life; the spread of irrationalism; the banalization of opular culture; the loss of willingness by individuals to take risks, to fend for themselves or think for themselves; economic stagnation and decline, the decleration of the rate of technological innovation...Everywhere you look, the writing is on the wall.

Mapping the trajectory of a spacecraft is a relatively straightforward business, bounded only by the laws of physics. Mapping the trajectory of an idea through a political system, on the other hand, can be a dicey business.

In fact, there ar no such things as "natural resources." There are only natural raw materials. It is human ingenuity that turns natural raw materials into resources.