Actually, it does make a lot of sense for Europe to form as one country. Copy the US Constitution, and go from there. Just keep it more federated like we’re supposed to be. Actually, I think Europe would be better at this than we are, as their states would guard their sovereignty a lot better than ours have!
No, it doesn’t make sense for it to be one country.
The model is more the Old Swiss Confederation, where each canton/country was/is practically independent but pool together against outsider aggression.
The USA is a country - but hte states haave slightly less freedom than German Landen and much less freedom than Swiss Cantons.