Like many people, Styx is confused about what “leftist” economics actually is. As Murray Rothbard demonstrated, state-socialism was a reactionary effort that had its intellectual roots in Counter-Enlightenment thinkers like Jean Jacques Rousseau and G.W.F. Hegel. What Americans think of as “socialism” is really progressivism, i.e. the deification of the public administration state that was developed in Prussia in the 19th century, and imported into the US by intellectuals educated in German universities in opposition to America’s classical liberal tradition. English Fabianism is a comparable tradition, one based on the furtherance of supposed social reform through the enlightened management of the educated classes. As Noam Chomsky and Larry Gambone have argued, the central thrust of historic socialism was always something more like anarchism. It was in the 20th century that socialism came to be identified with statism due to its cooptation by progressives and Fabians (“social democrats”) in the Western countries, and its subversion by Bolshevism in the Eastern countries.
And not to sound like Dinesh D’souza here, but it could be argued that between the 1860s and 1960s, the Republicans were the more left-wing party in the US. Certainly, that was true in the Civil War era when the Republicans were the party of the liberal-capitalist industrial bourgeoisie with the Democrats being the party of the agrarian gentry and semi-feudal slavery. Beginning in the Progressive Era, the Democrats were a coalition of Southern agrarian racialists and Northern progressives who admired the Prussian model, with the Republicans being a liberal bourgeois party that was often to the left of the Democrats on black civil rights issues, and that’s more or less how it was until the 1960s when the Democrats did an about-face on civil rights, and the Nixon Republicans brought the segregationists into their camp.