President Trump's administration hasn't been shy about wanting to put people back on the Moon, and now it's taking action to make sure that happens. In a statement, the White House said the President would sign Space Policy Directive 1, which orders NASA to lead an "innovative space exploration program" that sends astronauts to the Moon and, "eventually," Mars. Details of what the policy entails aren't available at this point, but the signing will take place at 3PM Eastern. The date isn't an accident -- it's the 45th anniversary of the landing for the last crewed Moon mission, Apollo 17.
Vice President Pence shed some light on the motivations in October. The symbolism of returning to the Moon is a factor, of course, but Pence also saw it as a way to "build the foundation" for trips to Mars "and beyond." Both the presidential transition team and NASA's director nominee Jim Bridenstine have floated the possibility of mining the Moon, but there's no immediate indication that this will be part of the directive.
Whether or not the strategy is a good one is up in the air. Some support Pence's approach, arguing that the US needs more recent experience with human exploration than the Apollo missions before it travels all the way to Mars. It could also help create a lunar station that simplifies Mars voyages. However, there are concerns that the insistence on a moonshot won't help much, and may only serve to delay a visit to Mars at a significant expense to the public. And of course, there's the question of this being used to justify a shift away from the climate science that the current administration hates so much. Whatever the reasons, the debate is largely moot -- the US is going to try for more astronauts on the Moon.