[rhino369]

There isn't a good solution to this problem. And it's a problem Americans often have a very hard time understanding due to cultural differences.[1] But the world does step in occasionally to stop one ethnicity from beating up another even within the same country. NATO did so in Yugoslavia.

But it's also used as an excuse for expansionism. The build up to WW2 was Germany doing this exact thing.

But post WWII European history also has a lot of ethnic regrouping. All Germans were put back inside Germany. Borders are drawn to group people. Mixed ethnic nations broke apart into single ethnic countries.

This question is at the heart of the blood bath in twenty century Europe.

[1]- Americans treat ethnicity very differently than most cultures since we have such diverse ethnicities with no little to no cultural heritage leftover. America entirely decouples ethnicity and nationality. So it seems strange that it's such an important force in other countries.