No, Deneen is not a reactionary fantasist...
and no, he does not deny liberalism's accomplishments: "First, the achievements of liberalism must be acknowledged, and the desire to 'return' to a preliberal age must be eschewed. We must build upon those achievements while abandoning the foundational reasons for its failures. There can be no going back, only forward." -- Why Liberalism Failed , p. 182 This passage highlights a danger I noted in Oakeshott on Rome and America : while for several centuries Romans simply respected and followed the mos maiorum , the way of the ancestors, when their traditions began to break down, there arose a brand-new traditionalist ideology . Whereas previously Rome's traditions had been followed in an organic way, one which allowed them to also be organically modified, once they began to break down, a faction arose demanding that those traditions be turned into rules , and that those rules must be followed without deviation (and thus without allowing any organic response...