The great majority of crimes involve state prosecutions for violations of state law. However, just as state legislators make laws prohibiting criminal behavior at the state level, Congress defines and penalizes acts that constitute crimes at the federal level.
Federal criminal laws must be tied to some federal or national issue, such as interstate trafficking in contraband, federal tax fraud, mail fraud, or crimes committed on federal property. Some criminal acts are crimes only under federal law. But many criminal acts, such as bank robbery and kidnapping, are crimes under both federal and state law and may be prosecuted in either federal or state court.
Most crimes that come to mind—murder, robbery, burglary, arson, theft, and rape—are violations of state law. State legislators have used their general police power to regulate the conduct and the state has jurisdiction (the power to decide the case).
There are fewer classes of federal crimes because, while state lawmakers can pass just about any law (subject to review by courts for constitutionality), federal lawmakers can pass laws only where there is some federal or national interest at stake. For example, counterfeiting U.S. currency is a federal offense because it is the federal government's duty to print money.
In practice, federal interest is very broadly defined. The federal government has jurisdiction over the following crimes:
There are many differences in state and federal criminal prosecutions. Federal judges are appointed for life by the president, whereas state court judges, even those appointed by the governor, must sit for re-election. Federal crimes are prosecuted by Assistant U.S. Attorneys and investigated by federal officers, such as FBI, DEA, or ICE agents. State crimes are investigated by county sheriffs, state agents, or local police officers, and prosecuted by state district attorneys or city attorneys. As a very general rule, because there are far fewer federal prosecutions, cases in federal court can take longer to resolve.
Although it does not happen very often, there are no constitutional bars to prosecution in both state and federal court for the same criminal act if it violates both state and federal law. What about the Double Jeopardy Clause? While the constitutional prohibition against double jeopardy usually bars being tried twice for the same crime, there is a "separate sovereign" exception. Since the state and federal governments are separate, the Double Jeopardy Clause does not apply.
For example, in 1992, a jury in California state court acquitted four Los Angeles Police Department officers of beating Rodney King at a traffic stop. Later, federal prosecutors charged the officers with violating King's constitutional rights and two officers were convicted.
While the constitution allows dual sovereign prosecutions, states can prohibit such prosecutions through their state laws. For instance, New York statute prohibits a state prosecution when the same criminal act has been prosecuted under federal law and both state and federal laws are designed to prevent the same types of harm. (N.Y. Crim. Proc. Law § 40.02 (2020); People v. Manafort, 187 A.D.3d 612 (N.Y. App. 2020).)
As a practical matter, dual prosecutions like these are rare because resources at both the state and federal levels are limited.
Like state crimes, the penalties for federal crimes vary. There are advisory federal sentencing guidelines, and the vast majority of federal judges follow the guidelines when sentencing defendants. As a general rule, federal penalties are longer than state penalties for similar crimes. In particular, federal drug crimes carry harsh mandatory minimum sentences. People convicted of federal crimes and sentenced to prison will go to federal prison rather than state prison.
For more information on penalties for state crimes, see Classification of Crimes: Felonies & Misdemeanors.
If you are charged with or under investigation for a federal or state crime, you should talk to a criminal defense attorney. For federal charges, it is important to see an attorney with experience representing people in federal court, as the rules that apply in federal court are very different from those in state court. Whenever you face criminal charges, you need an attorney who has experience defending those types of cases in the same court in which are you are facing charges. Whether in state or federal court, an attorney can help you navigate the criminal justice system and obtain the best possible outcome in your case.