There's no way to notify your population of an action without also notifying your enemies of that action. No argument exists, to my knowledge, that a nation-state can be successful without hiding some information from other nation-states, and therefore from its people, given my first sentence.

It's one reason we elect representatives, in fact.

How about the nation state stops having secrets that are making enemies for itself?

Considering there has never been a time in human history where a nation state has not had any opposition from other nation states, I suspect your suggestion is literally impossible.

I guess what you are saying is that nation states are not a good governing structure for progress, into the future? Who are our enemies? The enemies of my country are not necessarily my personal enemies. In fact I quite like many people who come from 'enemy' territories. There is a disconnect between the reality I experience in my everyday life and the one put forward but my/our government/s.

Switzerland has been mostly without enemies for most of its existence.

So about those swiss bank accounts, then...