If Trump orders military action against Denmark/Greenland, are there checks and balances within the military/courts/Congress that can stop him doing so, and will those checks and balances actually be able to stop him?

Basically, say that nothing dissuades him. He's made multiple declarations of intent, asked Denmark multiple times, and they say no. He offers more and more money, and they keep saying no. He places punishing sanctions, and they still don't buckle. So he says he needs to take military action because there is a credible threat that Russia/China/Iran/whatever are using Greenland to attack the United States, and even frames it as an act of self-defence.

As commander-in-chief, he orders the military to invade Greenland. Officially, he needs approval in the Senate, but there are creative ways around that. Even if most politicians (and even most Americans) do not wish the war to happen, what happens then? Will resolutions passed in the House, or anything else that happens politically or judicially be able to stop him?