Pan-European nationalism is a political term, apparently coined by Hannah Arendt in 1954, and used mostly as a pejorative, for a (hypothetical, or postulated) ideology of nationalism based on a pan-European identity. Arendt warned that a "pan-European nationalism" might arise from the cultivation of anti-American sentiment in Europe.
While a form of "European nationalism" was embraced by minor neo-fascist groups from the 1950s to the 1970s, the concept is often mentioned as a potential threat that did not, in fact, become reality.
In the 1950s, there were a number of neo-fascist splinter groups explicitly advocating for "European nationalism". In Britain, Oswald Mosley led the Union Movement, advocating its "Europe a Nation" policy, during 1948–1973. In 1950, Mosley co-founded the European Social Movement, collaborating with comparable groups on the continent. The organisation was mostly defunct by 1957, and was succeeded by the National Party of Europe, formed in 1962 by Mosley and the leaders of the Deutsche Reichspartei, the Italian Social Movement, Jeune Europe and the Mouvement d'Action Civique.
In their "European Declaration" of 1 March 1962, the National Party of Europe called for the creation of a European nation state through a common European government and an elected European parliament, the withdrawal of American and Soviet forces from Europe and the dissolution of the United Nations, to be replaced by an international body led by the USA, USSR and Europe as three equals. The territory of the European state was to be that of all European nations outside of the Soviet Union, including the British Isles, and their overseas possessions. The movement remained active during the 1960s, but mostly disbanded during the 1970s.