The curse of postmodern pseudoscience in most of the other answers. Postmodernism like Marxism was designed, like Abrahamic Religions, as an attack on European Peoples (civilization), to eradicate our civlization in the modern world just as Abrahamic religion was used to eradicate the five great civilizations of the ancient world: Roman New Europe), Byzantine (old europe), Anatolian, Persian (Iranic), Egyptian, and North African. All those civilizations were destroyed by the last attempt at cultural destruction. Why? Marxism/Postmodernism in the modern world, and Abrahamic Religion in the ancient world foster dysgenic rapid reproduction of the underclasses reversing genetic domestication under small farm mixed agrarianism, effectively weaponizing reproduction and ignorance and superstition against civilization. There are reasons that the Han, Koreans,Japanese and Europeans succeeded and other civilizations failed to maintain rates of innovation. The reason is that the Han, Koreans and Japanese remained insular and homogeneous, and whites succeed as long as they also remain homogeneous and practice eugenic reproduction through manorialism (meritocracy). The rest of the world did the opposite and the sizes of their underclasses pose such a burden that they cannot produce sufficient middle and upper classes to produce high trust commercially successful political orders.

Races, Subraces, Tribes, Clans, Families and Classes can interbreed, but differences matter. The primary differences are the degree of neoteny (white and east asian) vs deeper maturity (semites, iranics, africans, and australoids), the more feminine or masculine structure of the brain (yes really), and the size of the underclass due largely to winter climates, manorial farming, and close cohabitation in winters while caring for animals. (Or in the european and chinese cases, aggressive use of criminal punishment - particularly european hanging of large portions of the underclasses every generation).

Using size of class, degree of neoteny or maturity, and balance of masculine and feminine traits, each of the Races, Subraces, an sometimes Tribes, has evolved (adapted) for certain excellences that are geography, climate, means of production, and method of socialization dependent.

Human domestication like animal domestication, uses neotonic selection to suppress sexual maturity and preserve the features and cooperative intuitions of youth. The goal for any polity is to increase intelligence, industriousness, and trust. Counter to our assumptions the San (the oldest continuous tribe) were more gentle, and humans appear to have become increasingly AGGRESSIVE in some regions and increasingly GENTLE in other regions, which is easily measurable by group testosterone distributions, rates and ages of maturity, and ‘hardiness’ of features (deeper maturity). By the upward redistribution of reproduction (china, europe, and jewish) you increase the distribution of neoteny in the public largely by the reduction of rates of reproduction of the underclasses. The simple fact is that many people are a harm to their fellows simply because they are a drag on norms, laws, traditions, values, and institutions, literacy, technology, and the work force capacity - perhaps most importantly making a sufficient middle class to produce a voluntary organization of possible impossible, and forcing the dependence upon familial corruption (india, south america, south europe, all of islam) despite access to trade routes.

The optimum political order is homogenous - diversity is always and everywhere bad for obvious and well documented reasons. It trades short term profits for long term costs that destroy the political order and reduce it to levantine, south american, and indian levels of poverty and corruption.

The optimum political order is Small - The only value of scale military power to exploit others. The only value of federations is to produce defense of trade routes and prohibit rent seeking (corruption) on those trade routes.

And any group of size (the east asians) who succeed will leave the rest of the world behind. The europeans managed by the late middle ages to nearly eliminate their underclasses. This is why european intelligence is dropping (the flynn effect is reversing). Not because of individuals. But because of restoration of their underclasses. If Norway can lose IQ (they have) then any group can.

Smarter people are more moral - simply because they can afford to be.