The Greenland topic has the potential to disrupt the relations with Europe (and the NATO, by association) even more than the Ukraine/Russia one. Today he announced new 10% tariffs, to be increased to 25% in June if Greenland isn’t sold to the US.
Enforce is not the right word. The court can't enforce anything really, they don't control and police or army, they rely on the Executive to enforce anything. Really they only have moral suasion.
