Why does acton see the principle of nationality as dangerous to liberty

The principle of nationality for Acton emerges together with the idea of defending one 's own identity. For doing so, this feeling that comes with the principle of nationality would require the sacrifice of those against it. In the process of creating a private society, the principle of nationality could turn into something uncontrolable with a thirst to kill others in order to affirm one's own. That is dangerous as it calls for corrupted people who could kill in the name of a liberty they think is under threat. The threat would come from different views shared by different nationalities. If the customs and traditions of one nationality endanger another one, there could be death. Then the liberty of choosing how to behave could be dangerous. The answer or solution to such an issue is the law.