Multi-ethnic democracy is a harder mode than mono-ethnic democracy, which is why most comparisons of the US failures at various social policies to Scandinavian countries have always bugged me.
People don’t naturally feel as much allegiance to others who look and sound different. It takes time to overcome that.
I fully agree. Globally highly multicultural countries tend to be less stable on average, and it makes perfect sense if we consider basic human biology. We are tribal animals, it's hard to get around that.
Places like Sweden will have it even worse than the US, because migrants need to learn a fully new language to fully integrate, while most migrants to the US have at least some English skills to begin with.
People don’t naturally feel as much allegiance to others who look and sound different. It takes time to overcome that.