Concept
State Police Power
Constitutional Power to Exercise Criminal Jurisdiction
State Police Power
Every limit examined so far applied to Congress, which must trace each criminal statute to a grant in Article I and then survive the further restraints on that grant. A state criminal statute begins from the opposite position. The Tenth Amendment supplies the starting point: "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."1 The states existed before the Constitution and their legislative powers came first, so the framers carved from that existing mass only the portions they chose to give the national government and listed them, which left everything the list omitted vested in the states without change.2 The practical result is two different default rules. A federal statute needs an affirmative grant of power, while a state statute needs only the absence of a prohibition, because each state holds all governmental powers except those the people conferred on the United States, denied to the states, or reserved to themselves.3
The name for this general authority is the police power, meaning the power to legislate for the health, safety, welfare, and morals of the public, which includes law enforcement itself.4 In National Federation of Independent Business v. Sebelius the Court listed punishing street crime, running public schools, and zoning property among the functions the states perform even though the Constitution's text does not authorize any government to do so, and it identified the general power of governing that states possess and the Federal Government lacks as the police power.5 Criminal law is the most familiar use of that power, and the numbers show it: over 90 percent of all criminal prosecutions are brought in the state systems.6 State offenses are therefore the ordinary baseline, and a federal crime is the exception that needs its own justification.
An early decision shows the reservation at work. In Corfield v. Coryell a vessel had been seized, condemned, and sold under a New Jersey act because it was dredging oysters out of season, and the owner argued that Article III's grant of admiralty jurisdiction to the federal courts displaced the state's authority to punish that conduct.7 Justice Washington, sitting on circuit, rejected the argument. The power to regulate the fisheries in a state's waters and to punish those who transgress the regulations was exclusively vested in the states when the Constitution was adopted, and the mere grant of admiralty jurisdiction to the federal judiciary did not surrender it.8
The reason the Constitution leaves the definition of ordinary crime with the states lies in who answers for it. The framers rejected a central government that would act upon and through the states and designed two orders of government instead, each with its own direct relationship to the people it governs, so that a state's government represents and remains accountable to its own citizens.9 Madison described the reserved powers as reaching all the objects that concern the lives, liberties, and properties of the people and the internal order of the state.10 Defining a crime decides which conduct a community will punish with imprisonment, and placing that decision with a legislature the local voters can remove ties the definition to the people who live under it. The arrangement also lets states differ on questions such as the death penalty, so that one state's choice can be tested against another's.11
Broad authority is still bounded authority. The Tenth Amendment's own text excludes powers the Constitution prohibits to the states, so the reservation never covers what a prohibition forbids.12 In criminal law the most important prohibition is Art. I § 10, which forbids a state to pass any bill of attainder or ex post facto law.13 Those two bars can defeat a statute on a subject the state otherwise controls completely, because they restrict how the power is used and say nothing about whether the state holds it. The same restrictions bind Congress, which is why the defense is available against either sovereign. Further limits come from outside Art. I § 10: the Fourteenth Amendment's due process clause makes most Bill of Rights guarantees applicable in state criminal proceedings,14 and state constitutions sometimes protect defendants more broadly than the federal text does.15 Finally, state autonomy operates outside the Supremacy Clause, so a valid federal law that conflicts with a state statute displaces it, a point the next section develops.16
Students lose points when they demand an enumerated power for a state statute. That question belongs to federal legislation, and the state-side question is whether some prohibition or conflicting federal law defeats the statute.