I believe, as an european, that isn't much of a concern. We are very coupled to one another, plenty have family ties with other european citizens, share similar languages within immediate neighbours, and are culturally similar. Even religion is mostly shared. Of course, each has its own identity, not saying this isn't the case.

But without unity each one of us would just be yet another small country with a declining population, unity gives us strength.

The US leadership today thinks they are powerful enough by themselves. Quite a different perspective. Hence why sovereignty there seems to have a more patriotic meaning. I'm sure the states themselves still see the value of collaborating between themselves however.