Criminal law of the United States (2022): Overview

Responsibility for criminal law and criminal justice in the United States is shared between the states and the federal government.

Sources of law.

The federal government and all the states rely on the following.

Common law.

Common law is law developed by judges through legal opinions, as opposed to statutes adopted through the legislative process or regulations issued by the executive branch. A common law crime is thus a crime which was originally defined by judges.

Common law crimes no longer exist at the federal level, because of the U.S. Supreme Court's decision in United States v Hudson and Goodwin, (1812). The validity of common law crimes varies at the state level. Although most states have abolished common law crimes, some have enacted "reception" statutes recognizing common law crimes when no similar statutory crime exists.

Statutes.

All 50 states have their own penal codes. Therefore, for any particular crime somewhere, it would be necessary to look it up in that jurisdiction. However, statutes derive from the common law. For example, if a state's murder statute does not define "human being," that state's courts will rely on the common-law definition.

State vs. federal.

The states, since they possess the police power, have the most general power to pass criminal laws in the United States. The federal government, since it can only exercise those powers granted to it by the Constitution, can only pass criminal laws which are related to the powers granted to Congress. For example, drug crimes, which comprise a large percentage of federal criminal cases, are subject to federal control because drugs are a commodity for which there is an interstate market, thus making controlled substances subject to regulation by Congress in the Controlled Substances Act which was passed under the authority of the Commerce Clause. Gonzales v Raich affirmed Congress's power to regulate drug possession under the Controlled Substances Act under the powers granted to it by the Commerce Clause.

Model Penal Code.

The Model Penal Code ("MPC") was created by the American Law Institute ("ALI") in 1962. In other areas of law, the ALI created Restatements of Law, usually referred to just as Restatements. For example, there is a Restatement of Contracts and a Restatement of Torts. The MPC is their equivalent for criminal law.

Many states have wholly or largely adopted the MPC. Others have implemented it in part, and still others have not adopted any portion of it. However, even in jurisdictions where it has not been adopted, the MPC is often cited as persuasive authority in the same way that Restatements are in other areas of law.