Federalism

#### Definition
Federalism combines central and regional governments with divided powers.

#### Core Principles
- Division of powers, bicameralism, subsidiarity.

#### Historical Origins and Development
From ancient alliances; modern in U.S. Constitution.

#### Key Thinkers or Figures
- Johannes Althusius, Montesquieu.

#### Notable Variants
- Confederalism, asymmetric federalism.

#### Criticisms or Controversies
Risk of division or collapse.