You either spend a truckload of resources during decades to make a bomb that explodes releasing the same energy humanity spends in two months, or you spend a truckload of resources doing the end task at a slower pace for decades.
The later is guaranteed to require a smaller truckload.
Keep in mind that Greenland and Canada are both members of NATO, and thus the US would be forced to intervene...
Oh, well...
You mean seriously? Who knows? Both sides have nuclear weapons, don't they? This is not something that ever happened. Would the US armed forces go along with the plan or will there be a coup? Will everybody keep their heads leveled and avoid exchange nuclear explosions even with people dying at home / on the front? Will somebody just put a bullet on Trump's head and stop the madness?
But the thing I can tell is that if you are expecting country lines and military treaties to be immutable, that's not how they work.
You know, last time I've reached the MS forum, there was a support person there answering "No, there's no way to disable the Teams pop-up that appears over your shared screen when you mute the microphone. Lots of people ask the same question, and the developers have no plans of changing this".
The answer was complete, helpful, and completely out of the normal for the forum. The only thing more out of character would be if Teams actually had an option to make it work as any sane person would expect, but then, this is not on the forum people.
If you ever get curious, electrical engineering has lots and lots of convoluted procedures one can learn to avoid even more math... And civil engineering has a very cool "I can beat math with brute force and linear approximations all day long!" philosophy that could improve the lives of most people.
You either spend a truckload of resources during decades to make a bomb that explodes releasing the same energy humanity spends in two months, or you spend a truckload of resources doing the end task at a slower pace for decades.
The later is guaranteed to require a smaller truckload.