That's fine, but I was wondering "If NASA were to exert itself in a new attempt to land on either Mars or on our Moon, which should it be first?".
You seem to not understand how the system works. NASA does what it is told to do, the political system controls and funds NASA. So long as the great unwashed masses are unwilling to support NASA projects with taxpayer moneys NASA will do not much of anything.
Which of the two projects has the best chance of gaining support, and why, should be your question. On that it is clear that Mars is the one. We have already been to the moon, and short of some benefit for going again on the scale of mining a new energy source for Earth there is no reason to go back that is worth the effort. Mars on the other hand is a new place, it will require new technology which could turn out to be practically useful on earth, going to Mars does have a pay-off that makes the investment worthwhile.
I don't think that America can do this project until and unless we reform our political system, and even if we did it would make more sense for the ascending superpower that is China to lead this mission. I think that if America does bail on the space station that space is over for us, we will have proven to be not able to support major projects for the second time, first Skylab and now the Space Station. The Europeans don't have much of an Appetite for space, so that means that this endevor goes to the Chinese by default. Russia is basically a third world nation now and even more broken than America is, so they are no longer a contender.