On Greenland,

It is already a NATO colony with military bases. NATO would not object to more US presence as part of NATO mission. EU/Denmark would not object to FDI from US for resource exploitation.

The only possible reason for a US “national security” claim is that as a prelude to withdrawing from NATO, it needs to threaten EU further. Any economic exploitation is BS prohibitive due to lack of infrastructure, but if it happens it must be without fair compensation.