Why would nationalism lead to intolerance and persecution of other ethnic or national groups?

Nationalism can lead to intolerance and persecution of other ethnic or national groups because it often fosters a strong sense of identity and loyalty to one's own nation, which can marginalize those perceived as outsiders. This exclusivity can breed xenophobia, as nationalist sentiments may portray other groups as threats to national unity or cultural purity. Furthermore, when political leaders exploit nationalist fervor, they can incite divisions and justify discriminatory policies, leading to the scapegoating and persecution of minority groups. As a result, the emphasis on national identity often comes at the expense of social cohesion and tolerance.