The starting assumption of the article is that no one better exemplifies the social values of the new 'laissez-faire conservatism' evolving in the US in the 'postbellum' era than William Graham Sumner. There can be little doubt that Sumner, the first American sociologist of international note, can be considered to be the leading American exponent of Social Darwinism in the final decades of the 19th century. In his essays and in his major work, the monumental Folkways he tried to demonstrate that the wealth of society can be best promoted by championing the ideas of economic laissez-faire. In harmony with the tenets of Darwinian evolutionary theory he resolutely rejected the idea of government interference in economic and social matters. Consequently, it is not without reason that his oeuvre has been described as 'Spencerism in American dress'.