I'm guessing Trump wants to go back to the moon because the Chinese are planning to land there in approx. 2026 (continuing on from the past Chinese missions where they photographed the whole moons surface). A few people (world wide) were worried about how China might conduct itself while there
Maybe a few people have been whispering in Trumps ear and got him into a moon race.
Personally (even given the economic climate) I'm glad the US are choosing to go back to the moon. Imo, it makes more sense to use that as a stop off point for the Mars missions in future (and so much research has already done that it should be an easier mission overall). Plus, Helium 3 (found on the moon) can probably be turned into a fuel source for the Mars missions (way more cost effective, and safe, then shipping fuel into space from Earth).
I'm guessing there had been much debate (over the last few decades) at NASA as to wether diamond (nano) filament would be invented first (I've heard talk of this since the 1970's). If this filament had been made, we would have elevators into space from the Earths surface (saving fuel and the environment). However, this tech is still in the research and development stage. So it's expensive and they wouldn't have worked out yet how easy it is to produce, how cost effective (etc).