“History teaches that multiethnic states are held together either by an authoritarian regime or a dominant ethnocultural core, or they are ever at risk of disintegration in ethnic conflict.” ~~ Pat Buchanan
All the history I’ve read and mountains of sociological studies show that diversity in close proximity causes friction at best and wars at worst. This is true in every place and time in history. America 2016 is no different. We’re not awesome enough to be “past” it. Many of the problems our society deals with stems from its penchant for a multicultural experiment. So, in this view, promoting ethnic homogeneity is to promote peace while promoting the opposite, even if unintentionally, is to promote political and economic instability and social tension or war.
And the flip side is also proven: it’s those countries which are homogeneous that are the more peaceful, prosperous, stable, etc. Most liberals, for instance, want America to become more peaceful, “tolerant”, prosperous, beneficent, etc like Scandinavian countries; but those countries are nearly entirely white (homogeneous):