This chapter critically investigates the ideological underpinnings of contemporary far-right identity politics in Europe. It emphasises how these foundations influence contemporary discourses on Islam, “otherness” and European identity within the far right. The first section investigates civilisationism (Brubaker, Ethnic and Racial Studies, 2017). Civilisationism is understood as an ideology that, like orientalism (Said, Orientalism. Pantheon Books, 1978), portrays Islam as a culture antithetical to the West. Originating in liberal European culture and a culturalised civic nationalism, civilisationism has been appropriated by the contemporary far right to gather support from voters previously associated with the so-called mainstream. In contrast, ethnonationalism is an explicitly antiliberal and anti-universalist ideology that perceives identity as an expression of a mythical original difference. The second part of the paper examines the ideological foundations of ethnonationalism in the contemporary far right. Examining the works of the so-called conservative revolutionaries Oswald Spengler and Carl Schmitt, ethnonationalist decisionism is described as an ideology that, in moments of crisis, reaffirms the mythical notion of original difference, pointing to an “authentic” will. Spengler and Schmitt can be considered classic influences on the contemporary New Right. The final part of the paper will explore how ethnonationalism and ethnonationalist decisionism manifest in the New Right and its ambivalent relationship with Islam and the West.