What has modern life retained of the 3.7 billion years it took to develop human nature? Any biological or cultural system that did not promote successful survival and reproduction became extinct and human nature is what we have left from the winnowing process. Those retained traits should help us define natural law and human culture---assuming we stop denying the traits of human nature which developed over thousands of years.
Of the three brains which we retained, one evolved upon the other, we tend to try to culturally block the first two, the reptilian and the basic mammalian brains, in favor of the newer, less powerful, rational brain. For example, we try to rid ourselves of what we are, of our territorial, traditional, ethnopluralistic tendencies. But the "primitive" brain remains more powerful than the rational brain, which explains the cause of many of our neuroses. This has given rise to sociobiologically derived psychology (evolutionary psychology), which we hope doesn't drift into political correctness.
Thousands of years of grouping into ethnic communities and states and nations indicate that ethnopluralism is a natural process and to try to artificially tamper with this is to try to make human nature disappear. But the natural laws always reassert themselves and we return to the political configurations of real human nature, sometimes violently if human nature has been suppressed too much.
If the “deconstructionists” had said that all cultural and political practice was shaped by traits explained by sociobiology, one might agree with them, but instead they avoid biology and tend to say that culture was shaped by political considerations, in the manner of Marxism. or selfish power drives rather than by group selection. It turns out that many of the old traditions were in sync with human nature, they need only be brought up to date with an evolutionary conservatism, and with a philosophical (and I believe religious) sociobiology.
This is where the political philosophy directed toward an ethnopluralism of ethnostates dwells, which follows human nature as described by sociobiology, with theological materialism added giving teleological goals to evolution and human life.