From Robert Reich...

We are likely to hear a lot more about social Darwinism in the months ahead. It was the conservative creed during the late 19th century - legitimizing a politics in which the lackeys of robber barons deposited sacks of money on legislators' desks, and justifying an economy in which sweat shops were common, urban slums festered, and a significant portion of Am...erica was impoverished.

Social Darwinism encapsulated the idea of survival of the fittest (a phrase Charles Darwin never actually used) as applied to societies as a whole. Its chief apostle in America was Yale Professor William Graham Sumner.

Here's what Sumner had to say in his social-Darwinian classic "What Social Classes Owe to Each Other" (1883):

Let it be understood that we cannot go outside of this alternative: Liberty, inequality, survival of the fittest; not-liberty, equality, survival of the unfittest. The former carries society forward and favors all its best members; the latter carries society downwards and favors all its worst members.

Could there be a better summary of what today's regressive Republicans believe?