If you have never seen war up close then I am happy to forgive you, but trust me, in 'actual war' there is no possibility of success for anybody, there are only degrees of damage and degrees of grief and illusions to the contrary are focused on the few people that manage to get out of war with the profits in their pockets. Everybody else suffers.
1. Denmark cannot win militarily
2. You are suggesting Denmark would not capitulate and indeed enter into a state of war
What do you think happens in this situation?
Meanwhile they stand to lose a lot. There have been many NATO exercises that showed US aircraft carriers to be vulnerable to European submarines, so they can't park their fleet too close. They have to fly between NATO members Canada and Iceland. How would soldiers feel if they're forced to fight all their former allies? How would the US citizens feel?
Don't go around poking hornets nests if you don't want to get stung.
Make of that what you will, but if I were you I wouldn't go around poking the hornets nest that has an explicit sign "these hornets will sting" attached to it.
A nation that invades us is not friendly.
See, this is what is so dumb about this: you are treating this as if it is some kind of board game. It is exactly why the US gets into these messes over and over again, the incredible overconfidence that because they somehow have battlefield superiority they can do whatever they want. You are exemplifying precisely where the rot in the USA is located.
The one thing that is common about 'rationalists' is that they share a lot of the viewpoints with other ra*ists and that's not the world many of us want to live in.
Sure, you can take it. But can you afford to take it?
The answer is most likely you can't. And so far every attempt to show John Mearheimers superiority has been the equivalent of 'just relax and enjoy it'.
Guess what? We won't. Alliances are made voluntarily, not through conquest.