Hmm, i guess i'm still a curmudgeon. A chemical-powered Mars trip is possible, but i think unlikely. So far NASA has taken no steps towards such a goal. I figure it would take ten-fifteen years of research before we could launch. The first and most obvious step is to build a simulation of the Earth-Mars-Earth vehicle--a rotating tether with a reasonably robust life support system--something that could run for five years or so without resupply (arguably you could get oxygen from the Martian atmosphere, but pretty much everything else you're going to have to carry with you). NASA has little dinky projects on a closed life support system, but so far as i know (which isn't very) nothing that would work for anywhere near the mission duration.

A rotating space station seems a pretty obvious step--we need to know just how big it has to be for the astronauts to be able to function well, we need to know if there are any problems encountered in prolonged exposure to Mars gravity, we need to know what design constraints are important in rotating structures.

It would be nice to put a rotating structure in high earth orbit, so we could see how well the radiation shelter designs work.

Anyway, there are tons more details to be thrashed out. To do so would require setting a long term goal, and sticking to it. I don't see NASA or congress (put the blame where you like it) being able accomplish this without a better reason than we have now. Even the discovery of simple life might not be sufficient. On the other hand, if Hoagland's fantasies had some basis in reality, that would almost certainly provide sufficient motivation.

Anyway, i don't see the US (or any other country, with the possible exception of China) having the foresight and stamina to go for a chemical-powered Mars program with no more motivation than we have now. Nuclear propulsion (particularly high thrust high Isp nuclear propulsion) could change the picture completely.