Nationalism was the most successful political force of the 19th century. It emerged from two main sources: the Romantic exaltation of "feeling" and "identity" and the Liberal requirement that a legitimate state be based on a "people" rather than, for example, a dynasty, God, or imperial domination. Nationalism is a belief, creed or political ideology that involves an individual identifying with, or becoming attached to, one's nation.
There are various definitions for what constitutes a nation, however, which leads to several different strands of nationalism. It can be a belief that citizenship in a state should be limited to one ethnic, cultural, religious, or identity group, or that multinationality in a single state should necessarily comprise the right to express and exercise national identity even by minorities. The adoption of national identity in terms of historical development has commonly been the result of a response by influential groups unsatisfied with traditional identities due to inconsistency between their defined social order and the experience of that social order by its members, resulting in a situation of anomie that nationalists seek to resolve.
In Europe, nationalist thought has contained a central notion of racial superiority which has frequently been expressed in the display and use of military force - most vividly by Germany's Nazi government in the Second World War. Nationalism does not necessarily have a particular ideological slant, but varies from right to left on the political spectrum; its flavour and content depend upon the historical circumstances.
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