Griffin's theory, set out first in "The Nature of Fascism" in 1991, and more recently in "Fascism: An Introduction to Comparative Fascist Studies" (2017), offers a heuristically useful ideal type of fascism as a form of revolutionary organic nationalist movement, or palingenetic ultranationalism. For Griffin, fascism directly mobilises popular energies or works through an elite to eventually achieve the cultural hegemony of new values and the total rebirth of the 'ultranation', whether conceived as a historic nation-state or as a race or ethnos, from what it defines as the present state of decadence. Fascism is an ideology that has assumed a large number of specific national permutations and several distinct organizational forms. Moreover, it is a political project that continues to evolve to this day throughout the Europeanized world, though it remains highly marginalised compared with the central place it occupied in inter-war Europe, and its central role in identity politics has been largely replaced by non-revolutionary forms of radical right-wing populism.