Federalism — Constitutional Division of Power Between Federal and State Governments

Federalism is the constitutional architecture that divides sovereign power between the national government and the fifty states. The framers designed a system of dual sovereignty: the federal government holds only those powers enumerated in the Constitution (chiefly in Article I, § 8), while the states retain a vast residual authority — the police power — to govern health, safety, morals, and general welfare. The Tenth Amendment makes this explicit: "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." The Supremacy Clause (Article VI) simultaneously establishes that valid federal law preempts conflicting state law. The tension between these two principles — federal supremacy and state reserved authority — generates most of the constitutional litigation over who governs: Congress or state legislatures, the EPA or state environmental agencies, federal courts or state courts. Understanding federalism means understanding where the lines run and how courts police them.

Current Law (2026)

Legal Authority

• U.S. Const. art. I, § 8 — Enumerated powers of Congress: commerce, taxation, spending, war, necessary and proper; the affirmative grants that define the ceiling of federal legislative authority
• U.S. Const. art. VI, cl. 2 — Supremacy Clause: "This Constitution, and the Laws of the United States which shall be made in Pursuance thereof … shall be the supreme Law of the Land"
• U.S. Const. amend. X — Reserved powers: "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"
• McCulloch v. Maryland, 17 U.S. 316 (1819) — Federal power is supreme within its sphere; the Necessary and Proper Clause gives Congress implied powers beyond the enumerated list; states may not tax federal instrumentalities
• United States v. Lopez, 514 U.S. 549 (1995) — Reinvigorated limits on Commerce Clause: three categories of regulable activity; first statute struck on Commerce Clause grounds since the New Deal
• New York v. United States, 505 U.S. 144 (1992) — Anti-commandeering: Congress cannot compel state legislatures to enact or administer a federal regulatory program
• Printz v. United States, 521 U.S. 898 (1997) — Anti-commandeering extends to state executive officers; Brady Act requirement that sheriffs conduct background checks struck down
• Murphy v. NCAA, 584 U.S. 453 (2018) — Anti-commandeering bars Congress from dictating what states may NOT legislate as well as what they must legislate
• NFIB v. Sebelius, 567 U.S. 519 (2012) — ACA individual mandate upheld under Taxing Clause, not Commerce Clause; Medicaid expansion as originally structured was unconstitutionally coercive
• Gonzales v. Raich, 545 U.S. 1 (2005) — Congress may regulate purely intrastate economic activity under the Commerce Clause if it substantially affects interstate commerce in the aggregate
• 42 U.S.C. § 1983 — Civil cause of action for deprivation of constitutional rights by state actors, the principal vehicle for enforcing federalism's individual-rights dimensions against states

Key Mechanics

Federalism operates through four distinct doctrinal frameworks. Enumerated powers define the ceiling of federal authority: Congress can only legislate within the powers Article I, § 8 grants — principally the Commerce Clause, Spending Clause, Taxing Clause, and Necessary and Proper Clause. Preemption (Supremacy Clause, Art. VI) displaces state law when federal law expressly preempts it, impliedly preempts it (field preemption), or when state law conflicts with federal law. Anti-commandeering (from New York v. United States and Printz v. United States) prohibits Congress from conscripting state legislatures or state executive officers to administer federal regulatory programs — the federal government must use its own apparatus or offer incentives, not mandates. Spending Clause conditions allow Congress to attach strings to federal grants — conditions that states may accept voluntarily — but NFIB v. Sebelius (2012) held that conditions become unconstitutionally coercive when the grant is so large that states have no realistic choice but to comply, effectively converting a condition into a mandate.

How It Works

The Structural Baseline: Enumerated Powers and Reserved Authority

The Constitution's federalism bargain works in two directions simultaneously. Congress may legislate only pursuant to an enumerated power — chiefly the Commerce Clause, the Taxing and Spending Clause, the war powers, and the Necessary and Proper Clause (Article I, § 8, cl. 18). The enumerated powers are broad, especially after the New Deal Court's expansive interpretation of the Commerce Clause, but they are not unlimited. The Supreme Court's 1990s revival of federalism limits — Lopez (1995) and United States v. Morrison (2000) — established that the Commerce Clause covers channels of commerce, instrumentalities of commerce, and activities that substantially affect interstate commerce, but does not reach purely local non-economic conduct (possession of a gun near a school, gender-motivated violence).

Everything Congress cannot reach under enumerated powers belongs to the states by default. The states' police power — to regulate health, safety, morals, and welfare — is the largest domain in American governance. It encompasses criminal law (most crimes are state crimes), family law (marriage, divorce, custody, adoption), education (curriculum, teacher certification, school funding), land use and zoning, professional licensing, property law, and contract law. This default allocation is why there is no general federal police power: absent a specific enumerated-power hook, regulating ordinary crime, family life, or local commerce belongs to state legislatures, not Congress.

Preemption: When Federal and State Law Conflict

The Supremacy Clause resolves conflicts between federal and state law in favor of federal law — valid federal law preempts inconsistent state law. The federal preemption doctrine identifies three forms: express preemption (Congress explicitly displaces state law), field preemption (Congress has so thoroughly regulated a domain that no room remains for state law), and conflict preemption (compliance with both federal and state law is impossible, or the state law obstructs federal purposes). Courts presume against preemption when Congress legislates in a domain historically regulated by states; a "clear statement" of preemptive intent is required to displace state police power in sensitive areas. This presumption is the Supremacy Clause's counterbalance — federal supremacy where federal law speaks clearly, state authority otherwise.

The Anti-Commandeering Doctrine

The most judicially active branch of modern federalism doctrine is the anti-commandeering principle. The federal government may regulate private parties directly — it may not conscript state governments to do the regulating for it. New York v. United States (1992) struck down a federal requirement that states either regulate low-level radioactive waste according to federal standards or "take title" to the waste — Congress cannot force state legislatures to enact a federal statutory scheme. Printz v. United States (1997) extended this to state executive officers: the Brady Act could not require local sheriffs to conduct background checks on gun purchasers pending establishment of a federal database. Murphy v. NCAA (2018) completed the trilogy by establishing that the anti-commandeering prohibition bars "anti-authorization" statutes — Congress cannot direct state legislatures to maintain prohibitions that Congress prefers (the Professional and Amateur Sports Protection Act's ban on state sports-gambling legalization was struck).

The anti-commandeering doctrine has major practical implications. It is the constitutional basis for "sanctuary city" policies under which state and local law enforcement decline to cooperate with federal immigration detainers — the federal government cannot commandeer local police to enforce federal immigration law. It underlies state "Second Amendment sanctuary" resolutions refusing to enforce federal firearms regulations. It constrains federal environmental mandates that would conscript state agencies. The doctrine does not bar voluntary cooperative federalism, under which states participate in federal programs in exchange for federal funding — it only bars compelled conscription.

Spending Power Conditions and Cooperative Federalism

Congress uses the Spending Clause to achieve through financial incentive what it cannot mandate directly. By attaching conditions to federal grants, Congress induces states to adopt policies — minimum drinking age requirements (upheld in South Dakota v. Dole, 1987), Medicaid expansion requirements, highway safety standards — that it could not impose as direct mandates over state governments. This "spending power" mechanism underpins most of American cooperative federalism: Medicaid, Title I education funding, the Clean Air Act's delegated enforcement structure, highway construction, and Unemployment Insurance all operate as conditional grants.

NFIB v. Sebelius (2012) established a limit: conditional grants cannot be so coercive that they leave states no realistic choice but to comply. The ACA's Medicaid expansion conditioned all existing Medicaid funding on states expanding eligibility — threatening to strip funds amounting to over 10% of most state budgets. Seven justices held this crossed from permissible inducement to unconstitutional compulsion, effectively coercing states' participation. The outer boundary of coercive conditions remains contested and context-dependent.

Dual Sovereignty in Practice: State Courts and Federal Courts

Federalism also structures the judicial system. State courts are courts of general jurisdiction — they hear most criminal cases, family disputes, contract claims, and tort suits. Federal courts are courts of limited jurisdiction, confined to cases arising under federal law, diversity jurisdiction, or other Article III bases. Both court systems exist simultaneously: state and federal courts can hear some of the same cases (concurrent jurisdiction), while other matters belong exclusively to one system. The Eleventh Amendment further limits federal court power by granting states a form of sovereign immunity from private suits in federal court, absent their consent or congressional abrogation under Section 5 of the Fourteenth Amendment.

State courts must apply the federal Constitution when it applies, but they can also interpret their own state constitutions to provide more protection than the federal floor. A state court can hold, for example, that its state constitution bars warrantless searches even when the Fourth Amendment would permit them. This "adequate and independent state grounds" doctrine means that when a state court decision rests on state constitutional grounds, the U.S. Supreme Court has no jurisdiction to review it — the state court's interpretation of its own constitution is final.

The Current Federalism Map

Contemporary federalism disputes cluster around a handful of recurring conflicts:

Immigration: Federal immigration law is plenary — Congress sets who may enter and remain. But the federal government cannot commandeer state and local police to enforce that law. States may not obstruct federal immigration enforcement or enact their own alien registration schemes (Arizona v. United States, 2012), but they are not required to assist federal authorities.

Marijuana: Twenty-four states have legalized recreational marijuana; nearly all fifty allow medical use. Federal law (the Controlled Substances Act) classifies marijuana as a Schedule I controlled substance. Federal law preempts conflicting state law in theory, but the anti-commandeering doctrine means states cannot be required to enforce the federal prohibition. The federal government has largely declined to prosecute state-legal conduct under shifting enforcement priorities, but the underlying federal-state conflict remains unresolved.

Firearms: The anti-commandeering doctrine allows states to decline to enforce federal gun regulations. "Second Amendment sanctuary" laws in dozens of states instruct state officers not to cooperate with enforcement of federal firearms statutes. The federal government can still use its own agents (ATF) to enforce federal law — it just cannot use state police as a surrogate.

Gender and LGBTQ policy: A growing wave of state legislation restricts gender-affirming care, drag performances, and transgender bathroom access. Federal courts have applied varying standards of constitutional review. The federalism question is whether federal civil rights statutes (Title IX, Title VII, ADA) preempt inconsistent state laws — the answer varies by statutory scope.

Elections: The Constitution gives states primary authority over elections (Article I, § 4, "time, places and manner" clause; Article II, § 1 for presidential electors), subject to federal voting rights statutes and the Fourteenth and Fifteenth Amendments. Federal election law (HAVA, VRA) conditions federal funding and sets minimum standards but leaves most election administration to states.

How It Affects You

If you are an individual navigating the dual legal system: Federalism means that you are simultaneously a citizen of both the United States and your state — and that you can be prosecuted for the same conduct under both federal and state law without it being double jeopardy (the "dual sovereignty" exception). Most crimes that affect your daily life are state crimes tried in state courts. Federal prosecution is reserved for conduct crossing state lines, involving federal interests (tax evasion, immigration violations, crimes on federal land), or implicating federally protected rights. If state law protects you more than federal law — stronger privacy protections, more expansive civil rights coverage, better tenant protections — your state protections stand as long as they don't conflict with federal law. Federalism is the constitutional reason why marijuana is legal in California, why gun laws vary dramatically by state, and why education systems differ so sharply between states.

If you are a state official (governor, attorney general, state legislator): The anti-commandeering doctrine is your primary tool for resisting federal mandates. The federal government can regulate private parties directly; it cannot conscript your legislature to enact federal programs or your officers to enforce federal law. You can enact laws more protective than federal minimums (provided they don't conflict). You can decline to participate in federal enforcement operations (sanctuary policies) without violating the Supremacy Clause, as long as your state law doesn't affirmatively obstruct federal enforcement. You should, however, assess whether the funding conditions attached to major federal programs (Medicaid, education grants, highway funding) create practical compulsion — the NFIB coercion standard is rarely applied by courts, and most conditions are upheld.

If you are a federal agency or regulator: Your authority is limited to your enabling statute's scope, which in turn must fit within an enumerated constitutional power. Regulatory preemption claims must account for the presumption against preemption in areas of traditional state governance; courts will require evidence of clear congressional intent to displace state authority in health, safety, and police-power domains. The anti-commandeering doctrine means you cannot instruct state agencies to implement your program or direct state officers to enforce your regulations — you must build a federal enforcement infrastructure or use cooperative federalism grants with genuinely voluntary participation.

If you are a business operating across multiple states: Federalism produces legal fragmentation. You face 50 different state legal regimes for most substantive areas of law — employment, consumer protection, data privacy, professional licensing, environmental compliance — bounded by whatever federal floors apply. The Dormant Commerce Clause prevents states from discriminating against interstate commerce, providing some protection against state economic protectionism. Federal preemption can provide uniformity when Congress occupies a field. But in the large residual space where Congress has not spoken, you must navigate state-by-state variation. The federalism debate matters to you practically: broader Commerce Clause readings produce more uniform federal law; stronger state sovereignty produces more fragmented regulation.

State Variations

Federalism is itself the source of state variation rather than a doctrine subject to it. A few structural points:

State constitutions: Every state has its own constitution, and state courts may interpret state constitutional provisions more protectively than their federal analogues. California's constitution provides stronger privacy protections than the Fourth Amendment. Several state constitutions explicitly protect the right to an abortion. New York's constitution provides broader equal protection for sexual orientation than federal doctrine. When state constitutional law goes beyond the federal floor, it is insulated from Supreme Court review under the adequate-and-independent-state-grounds doctrine.

Cooperative federalism programs: States participate in major federal programs under different terms. Medicaid operates under waiver agreements that vary by state. Clean Air Act implementation plans (SIPs) differ by state based on local air quality and political choices. Unemployment insurance benefit levels are entirely state-determined within federal minimum-standards requirements. The degree of federal-state partnership, and the extent to which states have leveraged cooperative programs for local customization, varies enormously.

State-level federalism: Most states have their own internal federalism structures — counties, municipalities, and special districts with delegated powers. The relationship between state governments and local governments is called "Dillon's Rule" (localities have only powers expressly granted by the state) or "home rule" (localities have broader self-governance authority). This intrastate federalism is entirely a function of state law and state constitutional provisions — the federal Constitution imposes no structure on how states organize their internal governance.

Pending Legislation

No federal legislation is pending that would directly modify the constitutional structure of federalism — such modification requires either Supreme Court decisions or a constitutional amendment through the Article V amendment process. Several recurring legislative debates turn on federalism principles:

• Federal data privacy preemption: Congress has repeatedly considered a national data privacy law that would preempt California's CCPA and other state regimes, trading state-level protection for national uniformity
• Federal marijuana scheduling reform: Congressional proposals to deschedule or reschedule marijuana would resolve the federal-state conflict without eliminating state regulatory authority
• Voting Rights Act reauthorization: Following Shelby County v. Holder (2013), proposals to restore preclearance requirements for state election law changes implicate the federalism balance between federal oversight and state election administration
• Immigration enforcement cooperation: Legislative proposals both to require and to prohibit state cooperation with federal immigration detainers directly engage anti-commandeering doctrine

Recent Developments

• 2022 — West Virginia v. EPA, 597 U.S. 697 (2022): The Supreme Court invoked the Major Questions Doctrine to limit EPA's authority to restructure the energy grid through Clean Air Act regulation, without addressing federalism directly — but the decision reinforced limits on federal agency power over state energy policy.

• 2022–2025 — Post-Dobbs federalism: Dobbs v. Jackson Women's Health Organization (2022) returned abortion regulation to the states, producing the most dramatic state-level legal divergence since the pre-Roe era. Twenty-one states have enacted abortion restrictions or bans; seventeen states have enacted explicit protections. Federal abortion regulation proposals invoke the Commerce Clause as the power basis — the same enumerated power whose limits Lopez and Morrison established.

• 2023 — Biden v. Nebraska, 600 U.S. 477 (2023): Supreme Court struck down the Biden administration's student-loan forgiveness plan, invoking the Major Questions Doctrine and emphasizing that transformative assertions of federal administrative power require clear congressional authorization — a structural limit with federalism implications.

• 2024 — Moody v. NetChoice, 603 U.S. ___ (2024): Court addressed state laws (Texas HB 20, Florida SB 7072) regulating social media platforms' content moderation — raising whether states may regulate large platforms without conflicting with federal communications law or the First Amendment; remanded for further proceedings.

• 2025 — Trump administration executive orders on gender-related policy have generated numerous federal-state conflicts, with blue states invoking state authority and seeking injunctions against federal directives. The resulting litigation has raised questions about the scope of Spending Clause conditions and the limits of federal coercion in domains of traditional state governance (education, healthcare).