Module 2: Federalism & Congressional Power

Unlike state governments, Congress has no general police power — only the enumerated powers the Constitution actually grants it. The Necessary and Proper Clause, per McCulloch v. Maryland, lets Congress use means rationally related to carrying out an enumerated power, even without an independent, specific textual grant for that particular means.

The clause has real limits, though. In United States v. Comstock, the Court upheld a federal law allowing civil commitment of “sexually dangerous” federal prisoners past their release date, but only after laying out a five-factor test: the breadth of the Necessary and Proper Clause itself, the sound reasons for the statute’s enactment, the statute’s consistency with powers the federal government already has, the accommodation of state interests, and how attenuated the link is to an enumerated power. A means untethered from any real federal interest — not just a loose one — can still fail.

Example. Nothing in the Constitution explicitly gives Congress power to create a national bank. But since Congress has enumerated powers over taxing, borrowing, and regulating commerce, McCulloch held that chartering a bank is a rationally related means to exercising those powers — the Necessary and Proper Clause fills exactly this kind of gap.

In Wickard v. Filburn, the Court upheld federal regulation of wheat a farmer grew purely for his own consumption, never selling any of it — by aggregating the combined effect of many similarly situated farmers, reasoning their combined personal consumption substantially reduced demand in the interstate wheat market. This established a very broad reading of the Commerce power over economic activity, even at an individually trivial scale.

Wickard’s logic survived even the narrowing era decades later. In Gonzales v. Raich, the Court upheld federal drug law reaching marijuana a patient grew entirely within one state for her own medical use under state law, never selling or transporting it across any border. The activity was economic in the relevant sense — cultivation for personal consumption displaces demand in an interstate market for the same commodity — and Congress had regulated it as part of a broader, comprehensive scheme (the Controlled Substances Act), which the Court treated as reinforcing the aggregation logic rather than undermining it.

Example. Peter grows a small amount of wheat on his own farm just to feed his own family, never selling a single bushel. Standing alone, this seems far too trivial and local to matter to interstate commerce — but Wickard’s aggregation theory asks: what if millions of farmers like Peter all did the same thing? That combined effect on national wheat demand is substantial, which is enough to bring even Peter’s own small-scale, personal-consumption wheat growing within Congress’s reach.

United States v. Lopez and United States v. Morrison narrowed the Commerce power: aggregation theory only rescues Congress’s power over economic activity. Non-economic activity can’t be reached just by claiming an attenuated chain of effects on the economy. Valid Commerce Clause regulation generally fits one of three categories: channels of interstate commerce, instrumentalities/persons or things in interstate commerce, or activities substantially affecting interstate commerce (limited to economic activity).

NFIB v. Sebelius added a different kind of limit. The Affordable Care Act’s individual mandate — requiring most people to buy health insurance or pay a penalty — was not, the Court held, a valid exercise of the Commerce power at all, even though health insurance is obviously economic. The problem wasn’t the subject matter; it was that the mandate compelled people to become active in commerce rather than regulating existing commercial activity. Every prior Commerce Clause case, including Wickard, involved someone already engaged in an activity Congress then regulated — the mandate would have let Congress compel the activity itself, which the Court treated as a qualitatively different, unprecedented use of the power (though the mandate survived on separate taxing-power grounds, discussed below).

Example. Congress passes a law criminalizing gun possession within 1,000 feet of any school, reasoning that gun violence near schools eventually raises insurance and education costs, indirectly affecting the national economy. Simple gun possession isn’t economic activity at all — unlike Wickard’s wheat, there’s no production, consumption, or exchange of a marketable good here. Lopez struck down almost this exact law, refusing to extend aggregation theory to reach non-economic conduct through this kind of speculative chain of effects.

The Spending Clause is broader than Congress’s regulatory powers — Congress can spend for the general welfare, letting it influence areas it couldn’t directly regulate, by attaching conditions to funding. Under South Dakota v. Dole, conditions must be for the general welfare, stated unambiguously, related to the federal interest in the program, and not unduly coercive. NFIB v. Sebelius confirmed that last limit has real teeth: threatening to withhold an enormous amount of existing funding (not just new money) can cross from inducement into unconstitutional coercion.

NFIB actually shows the Spending Clause’s breadth from the other direction too. The same individual mandate that failed as a Commerce Clause regulation was upheld as a valid exercise of the taxing power instead — the Court read the “penalty” for going without insurance as functionally a tax, since it was collected by the IRS, calculated by reference to income, and didn’t carry the scienter or punitive labeling of a typical penalty. Congress’s ability to tax and spend genuinely reaches conduct it may have no direct regulatory power to command outright.

Example. Congress offers states a modest amount of new highway funding, conditioned on raising the drinking age to 21 — a real, if imperfect, choice states can decline, satisfying Dole. Compare that to Congress threatening to cut off all existing Medicaid funding a state already depends on unless it adopts an entirely new, separate Medicaid expansion — the sheer scale of what’s at stake, per NFIB v. Sebelius, can leave states with no real, practical choice, crossing into coercion.

The Tenth Amendment reserves powers not delegated to the federal government to the states. Two key cases give this real teeth: New York v. United States holds Congress cannot directly compel a state legislature to enact specific legislation, and Printz v. United States holds Congress cannot compel state executive officials to administer or enforce a federal regulatory program. This is different from conditional spending — Congress can induce state cooperation with funding, but can’t simply command it.

Murphy v. NCAA extended the doctrine in a direction New York and Printz hadn’t squarely addressed: a federal law can commandeer a state even by telling it what it cannot do, not just what it must do. A federal statute barred states from authorizing sports betting — it didn’t compel any state to act, only to refrain. The Court struck it down anyway, reasoning that a prohibition on state lawmaking is just commandeering by another name: either way, Congress is directly controlling how a state legislature exercises its own legislative authority, which the anti-commandeering rule forbids regardless of whether the command is phrased as a “must” or a “must not.”

Example. Congress can’t pass a law directly ordering every state legislature to enact a specific radioactive waste disposal law, and it can’t pass a law directly ordering local sheriffs to personally conduct federal background checks. Either would be unconstitutional commandeering. What Congress can do instead is offer states federal funding conditioned on voluntarily adopting a similar policy — a real choice, not a command.

Even without any actual federal legislation on a subject, the Commerce Clause itself — dormant, meaning inactive as to federal legislation — limits state laws that discriminate against or unduly burden interstate commerce.

Dean Milk Co. v. City of Madison is the real case behind the example below — Madison required all milk sold in the city to be pasteurized within five miles of the city, shutting out an Illinois processor located slightly farther away. The Court struck it down: adequate, less discriminatory alternatives existed (like on-site inspection of distant plants) to protect the city’s legitimate health interest. Where a law is not outright discriminatory but still burdens interstate commerce, Pike v. Bruce Churchsupplies the general test — the burden on commerce must not be clearly excessive relative to the putative local benefits.

Example. A state passes a law requiring all milk sold within its borders to be processed at an in-state facility, effectively shutting out otherwise-identical out-of-state milk producers. Even with no federal milk-processing statute at all, this kind of protectionist, discriminatory state law is vulnerable under the dormant Commerce Clause, since it burdens interstate commerce to protect in-state economic interests.

Tied back to Module 1’s Supremacy Clause: federal law can displace conflicting state law in three ways. Express preemption — Congress says so directly in the statute. Field preemption — inferred when federal regulation is so comprehensive that Congress must have meant to occupy the whole area. Conflict preemption — implied where complying with both laws is impossible, or state law obstructs federal objectives.

Arizona v. United States shows several of these working at once against a single state law. Arizona’s own immigration-enforcement statute created state crimes for failing to carry federal registration papers and for seeking work without authorization, and directed state officers to arrest people on probable cause of removability. The Court struck most of it down: the registration and work provisions were field-preempted, since federal law occupies alien registration comprehensively, and the arrest provision risked conflict preemption by threatening to interfere with federal enforcement priorities and foreign relations — a reminder that a state doesn’t need to contradict federal law word-for-word to be preempted by it.

Example. A federal statute explicitly states it “preempts all state laws on this subject” — express preemption, straightforward. Compare that to a federal law that says nothing about preemption at all, but makes compliance with a conflicting state law physically impossible — implied conflict preemption reaches the same result even without Congress ever saying the word “preempt.”