Understanding Federalism: How Power Is Divided Between Levels of Government
Federalism distributes governing authority between national and subnational governments. It was an American invention in its modern form, and it shapes nearly every major political debate in the country.
Published June 11, 2026When Americans debate whether a policy should be decided by federal law or left to the states, they are debating federalism. When a state passes a law that conflicts with a federal regulation, and courts must decide which prevails, that is a federalism question. When the federal government uses spending conditions to encourage states to adopt certain policies, that is federalism in operation. Understanding the structure helps make sense of an enormous range of otherwise puzzling political conflicts.
What federalism means
A federal system is one in which sovereignty is divided between a central government and constituent regional governments — states, provinces, cantons — each of which has its own authority and its own institutional existence. This is distinct from a unitary system, in which the central government is supreme and regional governments exist only at its discretion, and from a confederation, in which the constituent units are supreme and the central government derives its authority from them.
The United States was the first country to work out modern federalism in a written constitution, and the design reflected specific historical and political circumstances. The thirteen original states had existed as separate colonies with their own governments, laws, and identities. A purely centralized national government was not politically feasible and would have been difficult to administer across such a large territory with the technology of the late eighteenth century. Federalism was a compromise that preserved state authority while creating a national government with genuine powers of its own.
The constitutional division of powers
The Constitution grants the federal government specific enumerated powers: regulating interstate commerce, maintaining armed forces, coining money, and making treaties, among others. The Supremacy Clause establishes that federal law prevails over conflicting state law within areas of federal authority. The Tenth Amendment reserves all powers not delegated to the federal government to the states or the people.
The practical boundary between federal and state authority has shifted significantly over time. The Commerce Clause — Congress's power to regulate interstate commerce — has been interpreted broadly enough to encompass most of the modern regulatory state. The Civil War and Reconstruction amendments expanded federal power over civil rights. New Deal legislation and its constitutional validation by the Supreme Court in the 1930s extended federal authority over the economy in ways the original Constitution did not envision. Today's federal government has a much larger footprint than the framers anticipated, though significant state authority remains.
Cooperative federalism
In practice, much of American governance operates through cooperative federalism — programs in which federal and state governments share authority and funding. Medicaid, highway construction, environmental regulation, and education policy all involve federal funding with conditions attached, state implementation with local variation, and ongoing negotiation about which level controls what decisions.
The federal government cannot directly order states to implement federal programs — the Supreme Court has held that “commandeering” state officials to administer federal law is unconstitutional. But it can offer money conditioned on states doing what it wants, and states that want the money generally comply. This spending power is one of the federal government's most significant practical tools for shaping state policy in areas otherwise outside federal jurisdiction.
Federalism as laboratory and conflict
Federalism's defenders often cite the idea of states as “laboratories of democracy” — a phrase coined by Justice Louis Brandeis — in which states can experiment with different policies, and successful experiments can spread to other states and eventually the federal level. This is a genuine advantage: state-level policy experimentation has historically preceded federal action in areas like environmental protection, workplace safety, and healthcare coverage expansion.
Federalism also produces conflict and inequality. A right that exists in one state may not exist in a neighboring state. Environmental regulations may be stricter in some states and more permissive in others, which matters when pollution crosses state lines. The patchwork of state laws creates costs for businesses operating nationally and burdens on individuals who move between states.
Neither the centralizing nor the decentralizing impulse in American politics is consistently associated with a single ideological camp. The same political actors who want federal power used aggressively in one context often want state authority preserved in another. Federalism debates are ultimately about which level of government should make which decisions — and that question cannot be answered without also asking what decision is being made and who benefits from each possible answer.