Welcome to the international rules-based order!
Trump has re-iterated his belief that the USA has got to have Greenland, while Denmark and Greenland protest that you can't annex another country.
Unfortunately you can - as the Danes well know.
Turkey - a fellow NATO member - annexed Northern Cyprus in 1994 and Cyprus is still divided today.
NATO seems to be fine if the annexing is being done by NATO but not if it is done by somebody else.
It's the rule: Do as we say, not as we do!
While everyone protests Russia re-annexing Crimea it now seems that a repeat annexation of territory governed by one NATO member by another NATO member is more than an idle threat.
The excuse will be that it is a 'defensive' annexation not the offensive takeover of one country by another, which of course is what it is.
So that's alright then.