Definition
Federalism is a system of government in which sovereign authority is divided between a central (national) government and constituent (state or provincial) governments. In the United States this division was a deliberate design choice — the framers had just rejected the over-decentralized Articles of Confederation and were determined not to swing back to over-centralization.
Why it exists
How power is divided
Doctrinal anchors
| Doctrine | What it says | Source | |---|---|---| | Supremacy Clause | Federal law trumps conflicting state law | Art. VI, cl. 2 | | Preemption | Three flavors — express, conflict, field | Built on the Supremacy Clause | | Anti-commandeering | Federal govt cannot force state officials to enforce federal law | Printz v. United States (1997) | | Reserved powers | Powers not delegated to the federal govt are reserved to the states or the people | 10th Amendment | | Dual sovereignty in criminal law | Federal and state govts can each prosecute the same conduct without double jeopardy | Gamble v. United States (2019) | | Privileges and Immunities | A state cannot discriminate against citizens of other states in basic rights | Art. IV §2 |
The recurring tension
Why federalism is hard for any policy area
Almost every policy domain — healthcare, education, immigration, environment, labor — has a natural federalism profile. Some areas are intrinsically national (interstate transportation, currency, foreign affairs). Some are intrinsically local (schools, zoning, family law). But many sit in the middle and the boundary moves over time. Federalism debates are rarely about whether federal authority should exist; they're about where the line should be on this specific issue this decade.
Examples in current debates
- Cannabis legalization. State-legal, federally illegal. The Supremacy Clause is on the federal side; anti-commandeering and prosecutorial discretion are on the state side.
- Sanctuary cities. Federal immigration law is federal. Localities argue they can't be commandeered to enforce it (Printz-style).
- Abortion (post-Dobbs). Returning the question to the states is federalism in action — and produces a 50-state policy patchwork.
- Online sales tax. South Dakota v. Wayfair (2018) reshaped which states can tax which sellers across state lines.