Well, that’s the prospect noted by Rand Simberg, “recovering aerospace engineer and a consultant in space commercialization, space tourism and Internet security”:
The fly in the ointment is that it would require several hundred million dollars, to accelerate the development of both the launcher and a new cryogenic upper stage with sufficient impulse to throw the crew to Mars and back. If it’s not ready by late 2017, the window of opportunity will be lost. There’s another in 2021, but it’s a longer journey (though it does have the advantage of visiting Venus as well). Even if they can get Congress to appropriate funds for such a dramatic shift in policy (Tito believes that it has to happen within a couple months to hit their deadline), the risk of schedule slips will remain high, given the way NASA has managed such programs over the past few decades. Also, NASA issued a statement afterward  that seemed to splash cold water on the proposal … More.
Simberg speculates money and politics, but surely money is driving the politic:. Bail out 1) the Mars mission? 2) Detroit? 3) People hard hit by health care changes? Where are the votes headed?
Some of us suspect that only a human search on Mars would answer questions re life there. Put another way: How many remote or unusual life forms on Earth were discovered by instruments alone, as opposed to by someone slogging around in hip waders and insect repellent? See also: Don’t let Mars fool you. Those exoplanets teem with life!