satwai: 1) As far as I know, the idea was never put forth through diplomatic channels to Denmark. Tweeting is not anything official. Second of all, when Denmark's PM was told -- secondhand -- that Trump had said it would be a good investment, she said that it was not possible, that Greenland belongs to Greenland, not Denmark. When there was further discussion of the matter, she said it was absurd. When Truman purposed to buy Greenland it had a different status with Denmark than it does now. It is now considered an autonomous country and, as Denmark's PM first stated, Greenland does not belong to Denmark and so Denmark can't sell what it doesn't own. So the question is 1) Why didn't Trump know that and 2) Why does Trump think tweeting constitutes a diplomatic offer?