Mars may be a gleam in GW's eye,
when he has time to be distracted from grave world & economy issues, but I
think he's going for the go slow, pay-for-what-you-can-afford-now approach.
Meaning?
R&D the propulsion first; then R&D
the modules [one-by-one], bringing
in international partners to spread the cost; and then R&D the HLV boosters
that will be needed before launching
the hardware into LEO for assembly and prep.
The cost and R&D timeframe would probably be spread over twenty years
and over several presidential administrations.
Would President Hillary Clinton [2009-2013] approve of such a manned
Mars mission project?
Only [smirk] if they send her husband on a one-way trip.
cheers.

Jacob