I guess we're now going to see what will happen given the Greenland situation. Of course I don't want the US to be a dictatorship, and I don't want them to start expanding against international law. But I don't think the rest of NATO is going to militarily fight the US. The US obviously would have a much stronger hand in any conflict so a conflict would surely be pointless. Death and destruction for no gain, since the US would win anyway.

Perhaps more likely, if the US does invade Greenland, is that NATO in its current form would break up. A Republican congressman has said this sort of thing: "for [Trump] to militarily invade [Greenland] would... end up abolishing Nato as we know it".