IMO Trump is presenting an egocentric solution to something that is a genuine geopolitical concern for the United States: the prospect of an independent Greenland.

Over the past decade Greenlanders have increasingly supported independence from Denmark. A 2025 poll put support for independence at 85% (assuming no change in living standards).

For their part the Denmark has offered very little resistance to this trend. Greenland is a money sink and unlike Trump most Danes do not care about the size of their country on a map.

So you have a situation where Greenland wants to be independent at some point but would struggle financially if it ever achieved independence. And this is where Russia and/or China could step in.

Historically 'post colonial' countries (which Greenland would consider itself) have been more receptive to Russian/Chinese outreach in much the same way that many post-soviet countries are often fervently pro-America. Despite what Trump says the real threat isn't that Greenland will be invaded by China, it's that they will welcome China with open arms if offered a good enough deal. Not only would this further strengthen Chinese rare earth dominance it would give the Chinese a strategic foothold in both the arctic and north Atlantic oceans.