I don't see how it would actually work in practice. Can Trump really destroy Greenland's democracy via executive order? Surely Congress or the courts would have something to say about it? And even if not, how are you going to deal with all the people there? If Trump is ruling Greenland via executive order, then he is just a dictator, what happens to the people? It would end up as a long running sore and a terrible blemish on America's reputation.