The reason it's impossible to win a war against the current US military is because the US has spent an obscene amount of money building it for decades.
If the US military were not capable of defending Eastern Europe, Ukraine, Poland and the Baltics would be under Russian rule today.
Nukes prevent any war from happening between any powerful nation.
If we spent 1 tenth the amount on our military, we'd still have the power to blow up the entire world X times over.
I just think that if you have the ability to destroy the entire world, then that's a powerful enough military and you don't need anything more for defense.
The only thing preventing Eastern Europe from being invaded is the conventional military. The US will never risk it's own existence for another country. The Russians know this.
So no, I don't believe that the US would do that and I am happy about that.
The US would only use Nukes if there was an attack on the US.
I want the US to stay out of all wars that aren't directed related to attacks on US soil and US citizens.
If the EU is worried about invasion, then they should have their own military to defend themselves.
Cyber-warfare is going to be where it's at. You spend years infiltrating adversary networks, backdooring critical systems/infrastructure and exfiltrating intelligence so when the time comes for conflict, you already know what cards they're going to play, where all the pieces are on the map and you can shut it all down with a few commands. Then you start your blitzkrieg unopposed.
It's telling Russia, China and North Korea so heavily encourage cyber-espionage and malware development. Meanwhile in the US, we've got idiots passing laws criminalizing mere infosec research. We're handicapping ourselves against a threat our adversaries are all too eager to employ.
Wars between nuclear countries don't happen any more.