Would a lot of our issues be easier to solve if we had a very homogenous population?

>like public safety and crime rates, rail transit, political polarization, social trust, etc Aside from rail transit (wtf?) the answer to this is yes, it would be better in a homogeneous culture.  But the bigger issue is would that cause more problems than it fixes? People would get in fewer car accidents if we banned cars nationwide, but it's a ridiculous question to ask because the implications of the "solution" are ludicrous to even consider.  It's hard to be racist when you don't have any other races in your country, sure. But what's the point of discussing that? It's hard to have religious disagreements when you force everyone to be a single religion too. But.. is it really worth discussing if you aren't willing to force everyone to follow a single religion? And if you *are* willing to force everyone to follow a single religion, then you're probably not someone worth having a conversation with in the first place.  The answer to your question is yes. But I ask why you're asking the question at all if you're choosing to ignore every other aspect that the question implies.