What does "federalism" refer to in the U.S. legal system?

Federalism refers to the system of governance in the United States where power and authority are divided between the national (federal) government and the individual state governments. This division is foundational to the structure of the U.S. legal system, as it allows for both levels of government to have their own jurisdictions, powers, and responsibilities.

In practice, federalism enables states to enact and enforce laws tailored to their local populations while the federal government addresses broader, national concerns. This coexistence ensures a balance of power, preventing one central authority from monopolizing legislative control. It establishes a system of checks and balances that is essential for the functioning of democracy in the U.S.

The other options do not capture the essence of federalism as defined in the context of U.S. law. The hierarchy of federal courts focuses on judicial structure, while the structure of law enforcement pertains to the operational aspect of policing, and the relationship between federal and state laws looks more at their interaction rather than the foundational division of authority that defines federalism itself.