Let us assume for the sake of argument that the claims typically made by white nationalists about genetically inherited intelligence in relation to different racial groups are true, or even just partially true, and that this is relevant.
Would this significantly change how we should organize, justifying state-enforced racial hierarchy, and even possibly segregation or ethnic cleansing?
In my view, no. Perhaps this would be a different conversation if we were still living in the 1800s, but we are right now on the verge of breakthroughs in genetic engineering.
It may soon be possible for us to edit genes in children before they are born using new technology known as CRISPR.
If scientific research could specify genetic patterns linked to intelligence or potential intelligence, you could target those genes for editing in new children.
Since the claim made by the white nationalists from what I've observed tends to be that there is only a tendency for members of different racial groups to diverge in intelligence on a genetic basis, the solution need not be entirely race-based. Using this technology, you could improve not only the general intelligence of black & brown groups which tend to be the main subject of scrutiny by white nationalists, but whites, Asians, and so on.
The issue here arises in equal distribution of the new technology. It will likely be reserved for the ruling class. I would like to point out to white nationalists that if they are concerned with the general level of intelligence among all humans, that the best way to raise the general level of intelligence is not to attempt to deport non-whites or segregate the races.
In fact the way to raise the level of intelligence among humans is to stand in solidarity with non-whites, and advocate equal distribution of new technologies such as genetic engineering. I don't think that the type of capitalist system most of humanity lives under is capable of coping with the rapid technological advances we are experiencing today.
In fact, I think that enforcing economic hierarchy will be harmful to all of humanity, including white people. If future technologies such as radical life extension and genetic engineering are a privilege reserved for the very-wealthy and powerful, all of humanity will suffer as the ruling-class entrenches its power. And that even includes most the petit-bourg white anons on /biz/, I'd bet.
On the other hand, if we as an interlinked set of societies decide to move past the capitalist order and abolish it, we will have in our hands the opportunity to raise the average intelligence level for billions of future humans.
To me, this sounds highly preferable to prolonged racial infighting between different types of humans.
But when presented with this argument, what will white nationalists respond with? Their response may prove whether their interest concerning these arguments really is a concern for humanity's future, or if it's just an excuse for ideology. I suspect a mix of responses from them.