I just don't understand people who think #trump is motivated by anything other than his own greed or that of his business buddies. People are tying themselves in knots trying to explain it as if trump is some kind of 3d-chess-playing diplomat, as if he'll back down if you just call him your friend enough times.
He does not care if other people suffer consequences for his actions. The only way to stop him from doing something is to make it a bad deal for him personally, or for the people he listens to.
His brain is not complicated. Quite the opposite. Someone told him #Greenland has $trillions in untapped minerals. Trump thinks he can get it for the low cost of $millions, or the cost of a simple military direction, either of which will be paid by taxpayers, not himself. Trump loses nothing but gains wealth for himself and his inner circle. To him, that's a "good deal", and he'll say or do whatever he thinks necessary to make it happen.
Oh, it's going to cause #NATO to collapse? That doesn't even register in his calculation. He sees a profit to be made and that simply outweighs whatever bits of paper may have been signed by his predecessors.