There are a lot of countries 100 years or less old, that were parts of big european empires, unless you want to hold them accountable for what the foreign ruling class did.
Well ... it is societies which have a problem. As a German, my society is very old. As a country we are very young. But we would never think, that nationalism would not be a problem we had in our society.
Accountable implies a lot. But mindful we should be.
