The theory that individuals, groups, and peoples are subject to the same Darwinian laws of natural selection as plants and animals. Now largely discredited, social Darwinism was advocated by Herbert Spencer and others in the late 19th and early 20th centuries and was used to justify political conservatism, imperialism, and racism and to discourage intervention and reform.
It seems to me it would explain a lot about the behavior of Americans. I mean not only believe it but support it, think it is a good thing that makes us stronger?
Only the strong survive, only my tribe survives, the survivors are better than those who suffer and die young. Even better if they die before they can procreate.
This is an evil idea, but I am sure it is not as discredited as that definition claims. I know that many talented and capable persons suffer and die because they lack privilege not because they are less or weak. I know that many cheer their deaths. Evil walks the Earth.