Generally, "nationalism" is not capitalized. It's a common noun referring to the concept itself, just like "democracy," "capitalism," or "communism."
However, there are some exceptions:
* When referring to a specific nationalist movement: If you're talking about a specific group or movement, like "German Nationalism" or "Scottish Nationalism," then you would capitalize "Nationalism" because it's part of the name.
* When using it as part of a formal title: If "Nationalism" is part of a formal title, like "Department of Nationalism" or "The Journal of Nationalism," you would capitalize it.
Example:
* Not capitalized: "The rise of nationalism in the 19th century was a significant historical event."
* Capitalized: "He joined the Scottish Nationalist Party."
* Capitalized: "The Department of Nationalism is responsible for promoting national identity."
In short, use your judgment and consider the context. If you're unsure, it's generally safe to lowercase "nationalism" unless it's part of a proper noun or formal title.