What has changed is that this treaty directly with Greenland and Denmark, outside of NATO, becomes the Law of the Land in the US, ‘forever’, independent of NATO. Under the American Constitution, any treaty signed by the US is so entrenched that no Act of any legislature, nor even of the President himself, can legally order military action in contravention of that treaty. And under the Military Code and under general law, no military officer can obey an order that is not legal. Basically, it completely prevents Trump from issuing a legal order to invade Greenland. I am sure his military leaders will tell him this. In essence it completely protects Greenland from ever being taken over by America, with almost no gain by America except for access to the mineral resources. Incidentally, I see nothing that would prevent DENMARK from entering into an agreement with any another country to develop Greenland’s resources through a Danish company.
Nothing is stopping him from issuing an illegal order and his generals would be in more hot water by disobeying it than obeying it.
Any military is purpose built to remove individual autonomy. The ones who rise to the top are the ones who most believe in the chain of command. The idea that one of our generals (who have been purged during Trump’s second term) would disobey an order is laughable to me. Maybe every modern president has used the military in a way that is illegal according to US law, a treaty, or both.
His generals have already been told b their JAG lawyers that they can NOT obey such an order without being prosecuted, and no officer under them will obey such an order either.