What Is Federalism? How the US Divides Power Between Washington and the States
Federalism is the architecture of American government — two levels of sovereignty sharing the same territory and population. Wht);font-size:1rem;max-width:640px;margin:0 0 8px;"> Federalism is the architecture of American government — two levels of sovereignty sharing the same territory and population. When a state legalizes marijuana that is banned under federal law, when a state sanctuary policy conflicts with federal immigration enforcement, or when the federal government threatens to cut Medicaid unless states comply, federalism is at stake.
- Federalism divides power between the federal government and state governments — states retain all powers not granted to the federal government (10th Amendment).
- The balance of federal-state power has shifted dramatically since the New Deal — federal programs now touch healthcare, education, transportation, and housing in ways unimaginable to the Constitution's framers.
- States serve as 'laboratories of democracy' — testing policies like marijuana legalization, minimum wage increases, and healthcare coverage before federal adoption.
- Federalism creates policy divergence on abortion, gun control, and immigration enforcement — with Democratic-led states often adopting different rules than federal standards or Republican-led states.
Key Federalism Doctrines
| Doctrine | What It Means | Key Case |
|---|---|---|
| Supremacy Clause | Federal law is supreme over conflicting state law within federal authority | McCulloch v. Maryland (1819) |
| Anti-Commandeering | Federal government cannot force state officials to implement federal regulatory programs | Printz v. US (1997); Murphy v. NCAA (2018) |
| Conditional Spending | Federal government may attach conditions to grants but cannot be coercive | NFIB v. Sebelius (2012) |
| Preemption | Federal law displaces state law when Congress intends to occupy a field | Arizona v. US (2012) — immigration |
| State as Laboratories | States may experiment with policy approaches that can be adopted nationally | Justice Brandeis, New State Ice Co. (1932) |
Federalism in 2025-26: States as Resistance and Compliance
Democratic-led states and cities have adopted sanctuary policies limiting cooperation with federal immigration enforcement, citing the anti-commandeering doctrine — federal government cannot force local law enforcement to act as immigration agents. The Trump administration has responded by threatening to cut federal funding to sanctuary jurisdictions and deploying federal agents directly. Courts have repeatedly upheld anti-commandeering while allowing federal enforcement on federal matters.
The Republican budget reconciliation bill's Medicaid cuts in 2025 posed a federalism question: as the federal matching rate declines, states face the choice of making up the difference with state funds, reducing eligibility, or cutting services. States that expanded Medicaid under the ACA are most exposed. NFIB v. Sebelius's limit on coercive conditions means the federal government cannot automatically eliminate all Medicaid funding to force states to accept cuts, but it can reduce the matching rate, shifting costs to states.
California, New York, Illinois, Massachusetts, and other Democratic states have used state law to protect abortion polling, environmental standards, consumer protections, and LGBTQ+ rights against federal retrenchment. California has its own EPA waiver authority, allowing stricter auto emissions standards than federal law requires. The result is an emerging dual regulatory framework in some domains — businesses operating nationally must navigate both federal and blue-state standards simultaneously.
Frequently Asked Questions
Can states nullify federal law?
No. The doctrine of nullification — the idea that states can simply declare federal law void within their borders — was definitively rejected by the Civil War and subsequent constitutional development. The Supremacy Clause makes federal law supreme over conflicting state law, and states cannot nullify that. However, states can decline to enforce federal law with state resources (anti-commandeering), can challenge federal laws in court, and can create state-level legal regimes that effectively nullify federal law in practice (as with marijuana), relying on federal non-enforcement. This is practical non-compliance, not formal nullification.
What is the 10th Amendment and how powerful is it?
The 10th Amendment states: "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people." For most of the 20th century after the New Deal, the 10th Amendment was largely dormant — the Supreme Court held in United States v. Darby (1941) that it was merely a "truism." The Rehnquist Court revived it beginning in the 1990s through cases like Lopez (1995) and Printz (1997). It remains contested — its strength depends entirely on how broadly the Supreme Court interprets federal powers like the Commerce Clause.
How does the Dobbs decision affect federalism?
Dobbs v. Jackson Women's Health Organization (2022) explicitly returned abortion regulation to states, producing a classic federalism outcome — different states have radically different rules. This has created novel interstate questions: Can a state criminalize its residents for obtaining abortions in another state? Can a state ban abortion-inducing medications that the FDA has approved under federal law? Can federal prescription drug preemption override state abortion bans for FDA-approved drugs like mifepristone? These federalism tensions from Dobbs are working through courts throughout 2025-26.
