The president says Greenland needs to be a part of the US, and he wont rule out using military force.
The wife of one of his cabinet members tweets a picture where Greenland belongs to the US and captions it "SOON".
How is Denmark supposed the respond when the president is actively threatening them?
You have been acclimated to having a president who says crazy things. This is not normal.
I think almost nobody sees it actually happening, but just the fact that he is saying these things is insane.
However, if you think through the scenarios, the US is in a very strong military position and there's not much Denmark or the EU as a whole would be able to do about it. They could threaten a direct military response, on the basis of making the annexation more trouble than it's worth, but then you're just playing chicken with a significantly crazier enemy.
Most likely the EU would try to calm the waters, and offer a compromise peace / surrender plan along the lines of the one the US has offered Russia in Ukraine.
The biggest obstacle ought to be political opposition and public protests within the US itself, but right now the US government is in a position to just move fast and make things happen, what with the weak Congress and compliant Supreme Court.
I hope and believe it'll become much less likely after the midterms, with a Democrat-led Congress motivated to push back against the executive's excesses.
This is a path to madness and I'm really surprised that there are no saner heads in the US putting a stop to this before it gets even further out of control. I'm even more surprised at how many people in the US support this, either tacitly or even outright.