Hector writes:

Increasingly I have the suspicion that out of the set of three things (political freedom, social/economic equality, and racial/ethnic diversity), you can have two of the three but not all three. As a society becomes more ethnically diverse, people become increasingly unwilling to subordinate their interest to the common good, unless you coerce/propagandize them into it. Cuba and the old Soviet Union had diversity and equality without freedom: Sweden and Costa Rica have equality and freedom without diversity: the United States and Brazil have diversity and freedom without equality.