Denmark has a freakin' King. You guys are still a monarchy... Greenland is closer to the US than Europe, and we defended and gave back demark during WW2.

Demark provides almost no financial support to Greenland, and can't defend it. It will prove to be very strategically important as the ice caps melt.

Russia invaded Ukraine, and Demark lets russia use the Danish straights to transport oil despite the US asking them to not allow them entry. Demark has no way to protect it's own straits, how is it suppose to stop an invasion of Greenland from russia? How is it supposed to impose order and control the north artic if it can't even protect it's own straights?

These are very real security concerns from then US that a monarch can't address.