A nationalist movement or government is a definition for nationalism according to a dictionary. There is such thing as context. lol
It doesn't mean nationalism is a political structure.
It's a belief system just like Islam, Christianity, Judaism, Shintoism , Buddhism, Hinduism, Satanism etc.
Nationalism is an ideology not a political structure:
Nationalism is a complex, multidimensional concept involving a shared communal identification with one's
nation. It is a
political ideology oriented towards gaining and maintaining
self-governance, or full
sovereignty, over a territory of historical significance to the group (such as its
homeland). Nationalism therefore holds that a nation should govern itself, free from unwanted outside interference, and is linked to the concept of
self-determination. Nationalism is further oriented towards developing and maintaining a
national identity based on shared characteristics such as culture, language, religion, political goals and/or a belief in a common ancestry.
[1][2] Nationalism therefore seeks to preserve the nation's culture. It often also involves a sense of pride in the nation's achievements, and is closely linked to the concept of
patriotism. In these terms, nationalism can be positive or negative.
[3]
Thats why its not exclusive to a certain wing, because it is a way of thought.
And before I hear a wikipedia is unreliable comment, only imbeciles think that.