Fetter's stand on this issue further led him to oppose Georgist ideas like the land value tax. Mark Blaug, a specialist in the history of economic thought, credits Fetter and John Bates Clark with influencing mainstream economists to abandon the idea "that land is a unique factor of production and hence that there is any special need for a special theory of ground rent... This is in fact the basis of all the attacks on Henry George by contemporary economists and certainly the fundamental reason why professional economists increasingly ignored him."