Post-WWII, the victorious powers disavowed nationalism. They saw it as an ideology tainted by the fascist powers they had just defeated. This disavowal came with the assumption that nationalism would slowly wither away. However, nationalism was still clearly a powerful vital force in new post-colonial powers. In Western universities, various thinkers sought to explain this, the most influential being Elie Kedourie in the 1960s and 1970s. Seeing nationalism as an ideology, he sought to explain nationalism through the framework of a history of ideas.
Nationalism as an ideology emerged in the early 19th century created by the interaction of various influential though disparate strands of thought. Kedourie considered three thinkers central to the emergence of nationalism; Johann Herder, Immanuel Kant, and Johann Fichte. Herder's argument centred on humanity's division into distinct cultural groups. Kant's arguments of individual moral autonomy were combined by Herder into a conception of collective self-determination. This conception gained traction amongst the intelligentsia, who found that the notion of states being based on cohesive cultural communities provided a new basis for political legitimacy at a time when justifications based on religious and dynastic reasoning were losing influence. The idea of legitimacy based on cultural cohesiveness also promoted the interests and power of the intelligentsia by making them guardians of national culture. Thus arose nationalism, which based political legitimacy on cultural cohesion supported and propagated by an influential class.
This account makes little provision for areas which had a sense of nationhood before the 18th century such as Ireland, England and Vietnam. This does not explain why the intelligentsia was able to promote its preferred political project so effectively. It focuses on intellectual forces at the expense of examining material realities that underlay the social success of nationalism.
[P1] Nations come from nationalism. [P2] Nationalism is based on the ideas of various 18th and early 19th century thinkers, along with their synthesis and adoption by an intelligentsia seeking to justify a new political system in which they played a prominent role.
Rejecting the premises
[Rejecting P1] The characteristics of nations existed in many places before the period nationalism supposedly arose. [Rejecting P2] Focusing on the formation of these ideas does little to explain why they were so politically successful and took root.