Congress's Power to Define Crimes

Congress's Power to Define Crimes

The previous section established that a federal criminal statute is valid only if it traces to a power the Constitution delegates. The task here is to find where those powers sit in the text and to see what Congress must do to use them. For crimes the search has a distinctive shape, because Article I § 8 contains no clause empowering Congress to define crimes in general.¹ It contains a few grants aimed squarely at punishment, such as the power to provide for the punishment of counterfeiting the securities and current coin of the United States. It also contains a much larger set of grants over subjects like commerce, post offices, and the armed forces, which Congress may enforce with criminal penalties as a means.² Every federal crime therefore needs an enumerated hook, a specific delegated power that the statute serves, and locating it is the first question to ask of any federal criminal law.

The hook requirement exists because Congress exists by grant. A federal statute needs some arguable textual referent in the Constitution, and a single adequate power is enough to sustain it, so the inquiry asks only whether at least one delegated power reaches the conduct.³ Congress holds something like a general police power only when it legislates for the District of Columbia and other federal territory, and there the Constitution confers it in so many words.⁴ If no hook were required, the question for any federal crime would become whether the conduct is serious enough to deserve national attention, and that question has no textual answer and no stopping point. The hook test replaces it with a question about text, which a court can decide, and it leaves the great bulk of criminal law with the state systems, which bring over ninety percent of all criminal prosecutions.⁵

A hook supplies the power, and the form in which Congress must use it is legislation. Article I § 1 vests all the legislative powers the Constitution grants in a Congress made up of a Senate and a House of Representatives.⁶ Defining a crime and attaching a penalty is legislative work. In Youngstown Sheet & Tube Co. v. Sawyer, Justice Douglas observed in a concurrence that laws carry sanctions, one kind being fine and imprisonment, and that deciding sanctions should be applied and the force of the courts directed against people is an exercise of legislative power that the Constitution places in Congress.⁷ This allocation keeps the definition of crimes apart from their enforcement. The executive branch that investigates and prosecutes holds no power to make law, so it cannot write the offense it will later charge, and an official who could both define and prosecute crimes would answer to no other branch about what counts as one.

The same structure bars federal courts from supplying crimes that Congress has not defined. In United States v. Hudson & Goodwin, a libel prosecution over statements about the President and Congress left the circuit judges divided on whether the federal circuit courts could exercise a common-law jurisdiction in criminal cases, and the Court answered no.⁸ The reasoning began from the nature of the federal government. Its powers are concessions from the states, and every federal court other than the Supreme Court has only the jurisdiction given by the power that created it, so the legislature must first make an act a crime, affix a punishment to it, and name the court that has jurisdiction of the offense.⁹ Courts keep the implied powers that come with being courts, such as fining for contempt and enforcing order in the courtroom, but defining crimes against the sovereign is not among them.¹⁰ The civil side of the system rests on the same footing, since Erie Railroad Co. v. Tompkins declares that there is no federal general common law and that Congress has no power to declare substantive rules of common law applicable in a State.¹¹ Federal criminal law is therefore wholly statutory, and a court asked whether conduct is a federal crime looks to an act of Congress and to nothing older.

An act of Congress must also be enacted in the manner Article I § 7 prescribes. A bill has to pass both the House and the Senate and be presented to the President, who signs it or returns it with objections, and a vetoed bill becomes law only if two-thirds of each chamber repasses it.¹² A concurring opinion in Wyeth v. Levine states the full condition for a federal law to count as supreme: it must be made in pursuance of the Constitution, which means it must satisfy both the limit of enumerated powers and the procedures of bicameralism and presentment.¹³ The two requirements guard against different failures. The hook asks whether Congress had power over the subject at all, while the procedure asks whether Congress exercised that power through the step-by-step, deliberate process the Framers designed.¹⁴ For a criminal statute, whose sanction is the loss of liberty, the procedure guarantees that the House, the Senate, and the President each have a say, or that two-thirds of both chambers override the President, before conduct becomes punishable. A prohibition adopted by one chamber alone, or announced by the executive, is not a federal law, however clearly some hook would support it.

The hooks differ in how directly they speak to crime, and the sections that follow take them from the most explicit to the most general. The express punishment powers come first, because the text itself names the wrongs Congress may punish: counterfeiting the securities and current coin of the United States, and "Piracies and Felonies committed on the high Seas, and Offences against the Law of Nations."¹⁵ Treason follows as the one crime the Constitution defines for itself. Federal enclaves and territory come next, where the clause giving Congress "exclusive Legislation in all Cases whatsoever" over the seat of government, and over places bought with the consent of the state legislature for forts, arsenals, dockyards, and other needful buildings, reaches ordinary conduct inside those places.¹⁶ Last come the regulatory powers, chiefly the power to regulate commerce among the states, joined to the Necessary and Proper Clause, which connects a penalty to the regulation it enforces, and most federal crimes in force today rest on this footing rather than on a clause that mentions punishment.¹⁷

At the direct end of that range, a statute punishing the counterfeiting of United States coin needs no inference at all, because the clause names the wrong and is itself the hook.¹⁸ The outer edge appears in Corfield v. Coryell, where a vessel found dredging for oysters in Maurice River Cove was seized and condemned under a New Jersey statute. The challenger argued that taking oysters out of season was an old admiralty offense and that the Constitution's extension of the judicial power to admiralty cases therefore displaced the state law. The court rejected the argument. Offenses that were admiralty matters in England became cognizable in the federal courts only through an act of the national legislature, and although Congress may add offenses by further legislation, the power to regulate a state's fisheries and to punish violations had been exclusively vested in the states and was not surrendered by the mere grant of admiralty jurisdiction to the federal judiciary.¹⁹ The case marks a line that students blur: a grant of judicial power says which courts may hear a matter once it is a crime, and it gives Congress no power to make anything a crime.

The flip works because the Constitution gives Congress exclusive legislative power over places purchased with the state legislature's consent for forts and similar buildings, so conduct that lies beyond the national reach in the country at large lies within it on that ground.²⁰ Had the statute instead reached restaurants serving interstate travelers, the analysis would shift to the commerce power, which a later section takes up.

Finding a hook answers only whether Congress may define the offense, and it leaves open which tribunal may try it. In Northern Pipeline Construction Co. v. Marathon Pipe Line Co. the government argued that under any of its Article I powers Congress could create courts free of Article III's requirements whenever that course seemed expedient, and the opinion rejected the contention because it offered no limiting principle: the powers to regulate commerce and to punish certain crimes would let Congress hand the related adjudication to judges it controls.²¹ Where Article III applies, every legislative power in Article I is subject to it, so a hook for the crime supports the statute but cannot be used to build a court outside Article III.²² The later section on federal judicial power develops that second question.

The order of the steps is a matter of efficiency, and no hook outranks another: a power found at step three sustains a statute as fully as one found at step one. Steps three and four do most of the work on modern problems, because most federal crimes rest on regulatory powers. On a bar question that hands the examinee a statute and asks whether it is valid, the question translates to whether the statute is a valid exercise of the relevant state or federal power, so the answer should begin by naming the power.²⁶

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Express Punishment Powers

The first step of the hook search asks whether the Constitution itself names the wrong the statute punishes. Article I § 8 answers yes for a short list of wrongs. It authorizes Congress "To provide for the Punishment of counterfeiting the Securities and current Coin of the United States" and "To define and punish Piracies and Felonies committed on the high Seas, and Offences against the Law of Nations."²⁹ These clauses differ from the rest of the section's powers in what they authorize. Most federal crimes serve some other end, such as regulating commerce, and the penalty is only a means to that end. Here the penalty is itself the end the clause names, so the statute needs no chain of inference. The clause is the hook.

The subjects on this short list have something in common. Each concerns conduct that a single state is poorly placed to reach, or that threatens an institution the nation holds as a whole. Counterfeiting attacks the national currency. A forged note or coin passes from hand to hand across state lines, and the loss falls on holders everywhere, so fifty separate statutes would leave seams that a forger could use. The high seas lie outside the territory of every state, which means that no state legislature has a claim to the conduct, and a crime aboard a ship far offshore would go unpunished unless the national government could define and punish it. Offenses against the law of nations carry foreign-relations consequences, since a wrong done to another country or its people becomes a matter that foreign governments take up with the United States, not with the state where the wrong occurred. Granting the power in express terms means the nation need not depend on fifty legislatures, or on implication, to answer for these wrongs.

The wording of each clause also sets its reach. The counterfeiting clause names its object, the securities and current coin of the United States, so it supports a statute only to the extent the statute protects those instruments. The second clause gives Congress two jobs, to define the offenses and to punish them, but it limits the places and subjects it covers: felonies "committed on the high Seas" and offenses against the law of nations.³⁰ A clause reaches only the wrong it names, and a statute that borrows the label of one of these wrongs for conduct outside it gains nothing from the clause. This echoes a point made earlier: a court asks whether the delegated power actually reaches the conduct, and the words Congress uses to describe the power do not decide that question.

The postal power sits just outside this category, and the reason shows how the express grants differ from the rest. The Post Office clause says only that Congress may "establish Post Offices and post Roads."³¹ It says nothing about punishment. A statute punishing the theft of mail therefore rests on the postal power by the same route as most federal crimes: the power supplies the end of maintaining a working mail system, and the penalty is a means of protecting it under the Necessary and Proper Clause, which the sections ahead take up.³² On an exam, the practical sorting question is whether the clause itself speaks of punishing the wrong. If it does, as with counterfeiting, piracy, and offenses against the law of nations, the hook is complete at step one. If it speaks only of a subject, as the postal and commerce clauses do, the analysis continues to the means-and-ends inquiry.

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Treason

The express punishment powers give Congress the wrong and the penalty, and for piracy and offenses against the law of nations they give it the power to define the offense as well.³⁴ Treason reverses that arrangement. Article III § 3 writes the definition of the crime into the Constitution itself, so Congress comes to the subject with the offense already fixed and with authority over only one piece of it, the punishment.³⁵ Here the document takes the power to say what the crime is out of the legislature's hands.

The definition is short and closed. Treason against the United States "shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort."³⁶ That sentence names two forms of the offense. Levying war means taking part in armed hostility against the United States, and adhering to enemies means siding with a power at war with the nation and giving it aid and comfort, which is help that strengthens it. The text's use of the word only makes the list exhaustive, so conduct that is hostile to the government, even gravely so, is treason only if it fits one of the two forms.³⁷ Harsh criticism of the government, however bitter, fits neither.

The definition is paired with a proof rule that is just as demanding. No person may be convicted of treason unless on the testimony of two witnesses to the same overt act, or on confession in open court.³⁸ An overt act is an outward, observable deed, as opposed to a belief or an intention, so the rule forces the government to prove treason through something the defendant actually did. Two details of the wording matter. The two witnesses must speak to the same act, so one witness to a delivery of fuel on Monday and another to a delivery of maps on Friday add up to one witness for each act and two witnesses for neither. And the alternative to witnesses is a confession made in open court, meaning in the judicial proceeding itself, which leaves out a damaging statement made to investigators somewhere else.³⁹

Congress's part is confined to the penalty. The Constitution gives it the power to declare the punishment of treason and no more.⁴⁰ The contrast with the express clauses is exact: the piracy clause lets Congress "define and punish" piracies and felonies on the high seas and offenses against the law of nations, while the treason clause lets Congress do only the second of those two things.⁴¹ The reason lies in who prosecutes treason. It is a crime against the government itself, so the officials who would write a broad definition or a loose proof rule are the same ones the accused is said to have opposed. A legislative majority that wants to punish dissent therefore has a standing temptation to widen the offense or let a single witness suffice, and fixing both the definition and the proof rule in the Constitution removes that temptation at the source, because an ordinary statute cannot change either. Even the penalty has a boundary: no attainder of treason may work corruption of blood, which would strip a traitor's heirs of their inheritance, or forfeiture beyond the life of the person attainted.⁴²

The three checks that the examples run together can be applied directly to a treason statute or a treason prosecution on an exam.

Students lose this issue when they carry the open-ended Article I § 8 reasoning over to treason and assume that Congress may reshape the crime as it sees fit. For treason Congress sets only the punishment, and a statute that tries to do more fails because the definition and the proof rule are beyond its reach.⁴⁶

Federal Enclaves and Territory

The second step of the hook search asks where the conduct occurred, because Article I § 8 gives Congress a different kind of power over certain places than it has anywhere else in the states. The clause authorizes Congress "To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the Acceptance of Congress, become the Seat of the Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards and other needful Buildings."⁴⁸ Two kinds of place fall within those words. The first is the national seat of government, which reaches the United States by a state's cession and Congress's acceptance. The second is an installation such as a fort, magazine, arsenal, or dock-yard, which reaches the United States by purchase with the consent of the state legislature.

Inside those places, "exclusive Legislation in all Cases whatsoever" gives Congress the legislative power that a state legislature would hold in its own territory. Everywhere else in the states, Congress needs an enumerated power, because the Tenth Amendment reserves the remainder to the states. Congress has the expansive police power of a state only when it legislates for the District of Columbia and other federal territories, and there the Constitution confers that power in so many words.⁴⁹ A criminal statute written for such a place therefore needs no commerce connection, no punishment clause, and no chain of inference through the Necessary and Proper Clause. The enclave clause is itself the hook. Congress has used it in two ways: it has enacted offenses confined to the "special maritime and territorial jurisdiction of the United States," such as a federal murder statute, and it has adopted the Assimilative Crimes Act, which takes the criminal law that applies elsewhere in the state where the enclave sits and makes its violation a federal offense, with the state's definitions and penalties.⁵⁰

The clause has two halves, and each rests on its own reason. The exclusivity protects the national government from dependence. If a state controlled law and order at the Capitol or inside an arsenal, that state's decisions could hamper the United States on its own ground, so the Constitution gives Congress the whole legislative power over those sites. The consent condition does the opposite job and protects the states. Land inside a state is state territory, and the state's police power covers it. Giving up that territory is a decision for the state, so the text makes Congress's exclusive power over an installation depend on the state legislature's consent to the purchase, and it makes the District depend on a cession by particular states. Where the legislature has not consented, the clause's special power has not attached, and the analysis returns to the ordinary hook search.

Territories and the District of Columbia reach a similar result from a neighboring direction. The opinion in Northern Pipeline Construction Co. v. Marathon Pipe Line Co. surveyed older decisions on this point: where no state operates as sovereign, Congress exercises the combined powers of the national government and a state government, and the District is a place with no division of powers between the two.⁵¹ A criminal code for such a place is an ordinary use of that combined power, which is why territory, like an enclave, needs no separate hook.⁵² The consent condition has no counterpart in the territories, because no state's territory is being given up there.

Two errors recur on exams. A student who finds a fort or arsenal and then hunts for a commerce nexus has missed that the place alone supplies the hook. A student who treats every federal facility as an enclave has skipped the variable the clause makes decisive, which is whether the state legislature consented to the purchase.⁵³ Because the clause attaches to a place, it also supports a statute only for conduct at that place, and the same defendant's conduct elsewhere in the state needs its own hook.

Commerce and Other Powers

Most federal crimes rest on a regulatory power rather than on one of the express punishment clauses. The leading example is the Commerce Clause, which authorizes Congress "To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes."⁵⁵ That sentence names a subject, commerce, and says nothing about penalties, so a statute resting on it must reach the criminal law by a further step. The step is short. A rule about how a subject may be handled needs a consequence for breaking it, and a criminal penalty is an ordinary means of enforcement, so conduct inside the subject of a delegated power may be punished as a way of making the regulation work.⁵⁶ The Necessary and Proper Clause, taken up in the next section, carries that means-and-ends reasoning. The postal, taxing, and war powers follow the same pattern, since each names a subject and leaves the penalty to be justified as a means.

United States v. Darby shows a commerce-based prosecution in its plainest form. The Fair Labor Standards Act prohibited shipping in interstate commerce goods produced by employees whose wages and hours fell below the statute's standards, and the indictment charged an employer with that violation.⁵⁷ The Court held that the power to regulate commerce includes the power to prohibit it, so Congress could forbid the shipment and penalize the employer who made it.⁵⁸ The employer answered that the statute's true aim was to control wages and hours, a matter left to the states. The Court replied that the motive and purpose of a commerce regulation are for the legislature to judge, and that it is no objection that the regulation carries incidents similar to a state's police power.⁵⁹ That answer follows from how the grant is built. The clause is defined by its subject, so Congress's reason for using it does not enter the analysis, and any other rule would doom a great many federal crimes, because the states also punish theft, fraud, and violence.

The commerce power also reaches beyond the shipment. Congress may regulate intrastate activities whose effect on interstate commerce is substantial enough that regulating them is an appropriate means to a legitimate end, and Darby sustained the wage and hour requirements for production destined for commerce on that ground.⁶⁰ The subject is wide in another direction as well: in Gibbons v. Ogden the power to regulate commerce was held to cover navigation by vessels that carry only passengers and by vessels propelled by steam.⁶¹

That breadth was not always accepted. In United States v. E. C. Knight Co. the majority treated manufacturing as a local matter, with commerce beginning only when the product started on its final journey.⁶² Carter v. Carter Coal Co. likewise treated the power as limited to commerce itself.⁶³ Darby limited Carter Coal to the extent it conflicted with the substantial-effects principle.⁶⁴ Darby also overruled Hammer v. Dagenhart, which had held that Congress could not exclude the products of child labor from interstate commerce unless the goods were themselves harmful.⁶⁵ The older decisions survive mainly as the contrast that explains why the modern inquiry asks about the connection between the regulated activity and commerce.

Breadth has an edge, and the edge is the requirement of a real connection. A regulatory hook is a grant over a subject, so the statute must reach conduct with a genuine tie to that subject. If Congress could reach anything by saying it was regulating commerce, the list of enumerated powers would constrain nothing. The rule against that result is old: a measure adopted under the pretext of exercising a granted power, to accomplish an object not entrusted to the federal government, is invalid.⁶⁶ Courts apply the rule by laying the clause invoked beside the challenged statute and asking whether the statute squares with it.⁶⁷ The modern cases bring the same idea to crime. In United States v. Lopez the Court described the commerce power as covering the channels of interstate commerce, the instrumentalities of commerce, and activities with a substantial effect on commerce.⁶⁸ In United States v. Morrison the Court held that Congress could not rest the Violence Against Women Act on the substantial-effects category, reasoning that the violence was noneconomic and local in nature and that the statute had no jurisdictional hook, meaning an element confining it to cases within federal power.⁶⁹ This section keeps the claim modest: the statute needs a real hook, and a general interest in fighting crime does not supply one.

The taxing and spending powers supply a second family of hooks. Congress may tax an activity that it could not directly authorize, forbid, or control, and it may offer funds to the states on conditions, as when federal highway money was conditioned on states raising their drinking age to 21.⁷⁰ In South Dakota v. Dole the Court sustained that condition, explaining that objectives outside the enumerated legislative fields of Article I may still be reached through the conditional grant of funds.⁷¹ A criminal statute enters through the same door as it does for the postal power: a penalty for evading a federal tax protects the end of raising revenue, so it rests on the taxing clause by means-and-ends reasoning.⁷² The limit matches the one on commerce. In United States v. Butler the Court refused to enforce a plan that used a tax and an appropriation to control agricultural production, a matter beyond the delegated powers, because the tax and the appropriation were only means to an unconstitutional end.⁷³

Other grants fill out the list. Article I § 8 also gives Congress power to declare war, to raise and support armies, to provide and maintain a navy, and to make rules for the government and regulation of the land and naval forces, so military discipline codes rest on those clauses.⁷⁴ Section 5 of the Fourteenth Amendment lies outside Article I § 8 and lets Congress enforce that amendment by legislation, and in Katzenbach v. Morgan the Court sustained a provision of the Voting Rights Act as appropriate legislation plainly adapted to the aims of the Equal Protection Clause.⁷⁵ A dissent in Dickerson v. United States observed that action under § 5 must be congruent with and proportional to a constitutional violation.⁷⁶ Each branch of the Commerce Clause is also a separate grant, so a statute must fit the branch it invokes. Seminole Tribe of Florida v. Florida held that Congress could not use the Indian Commerce Clause to abrogate state sovereign immunity, and it described that clause as not coextensive with the interstate branch.⁷⁷

A delegated power is not cut back by the Tenth Amendment, which reserves to the states or the people the powers not delegated to the United States. In Darby the Court said the amendment merely restates that undelegated powers are reserved, and that it does not deprive the national government of the means appropriate to a granted power.⁷⁸ The logic is one of sequence. The amendment answers the question of what remains once the delegations are counted, so it cannot shrink a delegation that already covers the conduct. For a time the Court read it differently: National League of Cities v. Usery held that the commerce power could not directly displace the states' freedom to structure integral operations in areas of traditional governmental functions.⁷⁹ Garcia v. San Antonio Metropolitan Transit Authority overruled that decision, finding the traditional-function line unworkable and leaving the states' protection chiefly to the political process.⁸⁰

Printz v. United States shows both halves of the point. The Brady Act regulated handgun sales, and the dissent explained that the commerce power adequately supported that regulation of commerce in handguns.⁸¹ The statute still failed in part, because it directed state law enforcement officers to perform background checks, and the Court held that the Tenth Amendment forbids forcing state officers to administer a federal regulatory program.⁸² That holding did not end the federal objective, since states could participate voluntarily and Congress could continue the program on a contractual basis.⁸³ The commerce hook and the commandeering limit therefore answer separate questions. The connection to commerce explained why Congress could regulate the handgun trade at all, and the Tenth Amendment ruling concerned who could be conscripted to carry out the regulation, a limit the sections ahead take up.

The rewritten statute resembles the transportation offenses Darby recognized, since the power to prohibit transportation in interstate commerce has been sustained for stolen articles, among other things.⁸⁴ The thief who stays in town remains subject to the state's own theft law, because each state holds every governmental power that the people did not confer on the United States or deny to the states.⁸⁵

Students lose this issue by treating a statute's evident goal of reducing crime as if it named a power. Because Congress has no general power to punish crime, the answer has to name the clause, identify its subject, and show the statute's real tie to that subject.⁹⁰

Necessary and Proper Clause

The last clause of Article I § 8 authorizes Congress "To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof."⁹² The clause names no subject of its own and attaches only to powers granted elsewhere. That feature explains its importance in criminal law: the express punishment clauses cover a handful of wrongs, and this clause carries a regulatory power from its subject to the penalty that enforces it. The commerce, postal, and taxing hooks discussed above each reach a criminal statute through it, so the remaining questions are how far the reasoning extends and where it stops.

The clause received its classic reading in McCulloch v. Maryland, where Maryland resisted Congress's charter of a national bank. The objection had textual force, because no enumerated power mentions banks or corporations.⁹³ Marshall answered that the Constitution contains no phrase, as the Articles of Confederation did, excluding incidental or implied powers, and that the Tenth Amendment deliberately omits the word "expressly."⁹⁴ The reason follows from what a constitution is. A document that tried to list every means by which its great powers might be executed would read like a legal code, so it marks the main objects and leaves the lesser means to be deduced from them, and a government given large ends must be given the means to pursue them. On that view a bank was no separate end at all. It was a means, like a corporation, for carrying into effect the taxing, borrowing, commerce, and war powers.⁹⁵

The dispute turned on the word "necessary," and it was older than the case. Hamilton had read the clause to permit any law incidental, useful, or conducive to an enumerated power, while Jefferson would have allowed only laws without which the grant would be nugatory, and he feared that the broader reading would swallow up the delegated powers.⁹⁶ Marshall refused the strict sense that Maryland's counsel urged, and he illustrated why with an example from the criminal law. Punishing a violation of federal law is not among the enumerated powers, yet everyone admits that the government may do it. The postal power is executed by the single act of establishing post offices and post roads, and from that act the power to carry the mail was inferred, and from the power to carry the mail, the power to punish those who rob it.⁹⁷ Punishing mail robbery is essential to the beneficial exercise of the postal power though not indispensable to its existence, and the same is true of punishing perjury in a federal court. An indispensability test would invalidate nearly every penalty, since almost any institution can exist on paper without enforcement, so the clause asks for means that are appropriate rather than means that are unavoidable.

The modern Court states the test in Marshall's words: "Let the end be legitimate, let it be within the scope of the constitution, and all means which are appropriate, which are plainly adapted to that end, which are not prohibited, but consist with the letter and spirit of the constitution, are constitutional."⁹⁸ National Federation of Independent Business v. Sebelius repeated the formula as a grant of great latitude to Congress.⁹⁹ Because the formula has three separable parts, it is best run in order against any federal criminal statute.

The second step is deferential for a structural reason. Choosing among possible means requires weighing effectiveness, cost, and side effects, and a court that demanded the single best means would end up redrafting statutes. McCulloch therefore held that, once a means is appropriate and not prohibited, the degree of its necessity is for the legislature to judge.¹⁰³ United States v. Darby applied the same latitude when it let Congress choose means reasonably adapted to a permitted end even though they reached intrastate activity, including wage and hour records kept for intrastate transactions.¹⁰⁴ The deference has a stated edge. The modern Court strikes down an act of Congress only when the lack of constitutional authority is clearly demonstrated, yet it also says that deference on policy cannot become abdication on questions of law.¹⁰⁵

The third step is where an otherwise sound statute can still fail. The clause enlarges the methods Congress may use and leaves its ends where the Constitution put them. In United States v. Butler the Court accepted that the taxing power may serve as a means of carrying out another granted power, but it refused to let a tax and an appropriation be used as means to an end outside the delegated powers, and it condemned the use of a granted power as a pretext for reaching an object not entrusted to the federal government.¹⁰⁶ Courts and commentators describe the result in the same terms: congressional power has grown through broad readings of what is necessary and proper, but it remains limited.¹⁰⁷ A prohibited means is therefore invalid even when the end it serves is entirely legitimate.

Marshall's mail example supplies the pole where the clause applies. A federal crime of stealing or obstructing the mail is a criminal enforcement mechanism plainly adapted to the legitimate end of operating a postal system, so it is valid without any further hook.¹⁰⁸ The other pole requires a flip of one fact.

The hypothetical shows which fact carries the result. Nothing about the legitimacy of the end or the fit of the means changed between the two versions. Only the existence of a constitutional prohibition changed, and that alone was enough to defeat the retroactive provision.

The clause also reaches powers granted outside Article I § 8, since its text covers all other powers vested by the Constitution in the government or in any department or officer.¹⁰⁹ In Katzenbach v. Morgan the Court applied Marshall's formula to the enforcement power in § 5 of the Fourteenth Amendment and asked whether the means Congress chose was appropriate to the end it sought.¹¹⁰ In Missouri v. Holland the Court reasoned that, if the treaty was valid, the statute implementing it was a necessary and proper means of executing the powers of the government, and it upheld the Migratory Bird Treaty Act on that basis, leaving the limits on the treaty power itself to a later section.¹¹¹ The same clause supports the federal statutes that regulate procedure in the courts where federal prosecutions are tried.¹¹²

On an exam stem, students lose this issue by citing the clause without naming the power it carries into execution, because the clause has no content until it is tied to a delegated end. Each federal act must rest on some granted power, and the clause supplies the bridge from that power to the penalty.{{cite:32334070-ac24-46f5-aaea-7adcddb9d52d)}}