#### Definition
Nationalism is an ideology that holds the nation should be congruent with the state, promoting sovereignty, self-determination, and a unified national identity.
#### Core Principles
- National unity and identity: Shared culture, language, and history.
- Self-determination and sovereignty: Freedom from external interference.
- Political power from the nation.
#### Historical Origins and Development
Emerged in the late 18th century with the French Revolution. Developed through modernization and ethnosymbolism theories.
#### Key Thinkers or Figures
- Johann Gottfried Herder: Nationality and patriotism.
- Anthony D. Smith: Ethnosymbolism.
- Ernest Renan: Nation as daily referendum.