B
But the US could just leave. No need to have a costly war over it. And why Greenland, when invading Canada is probably easier?
Or just do nothing. Silently decide to not support other countries when they get attacked. But keep on using the joint radar bases in the north and the logistical hubs in central Europe.
This being a distraction and/or Trump the Conqueror wishing to turn more regions on the map US colored seems most likely to me.
In practice, the US doesn't need Nato to run bases in Greenland. They did so before without consent.
During WW2, US got permission to build bases in Greenland from a Danish diplomat. After the war, Denmark wanted the US to leave, but they simply didn't. 1951 Denmark joining Nato and these becoming Nato bases was a solution that saved face. And even then the US did build secret bases with Danish consent.
I share your view of Trump.
Just not that last part.
Secessions shouldn't be done lightly, and never under push from an outside power.
This was done in preparation of the wars in Georgia and Ukraine. I think we should have learned our lessons by now.
Just like we might dream of the US coastal states leaving the US and joining Canada. But such a thing happening in reality? The potential for chaos and violence is huge.