The criminal law sets the acceptable limits of conduct in society. Everyone is expected to obey the criminal law under penalty of punishment. The criminal law generally does not require you to perform an action; rather it forbids an unlawful action. Each state and the federal government has its own set of criminal laws.

Criminal Liability is what unlocks the logical structure of the Criminal Law. Each element of a crime that the prosecutor needs to prove (beyond a reasonable doubt) is a principle of criminal liability. There are some crimes that only involve a subset of all the principles of liability, and these are called "crimes of criminal conduct". Burglary, for example, is such a crime because all you need to prove beyond a reasonable doubt is an actus reus concurring with a mens rea. On the other hand, there are crimes that involve all the principles of liability, and these are called "true crimes".

Criminal law involves prosecution by the government of a person for an act that has been classified as a crime. Civil cases, on the other hand, involve individuals and organizations seeking to resolve legal disputes. In a criminal case the state, through a prosecutor, initiates the suit, while in a civil case the victim brings the suit. Persons convicted of a crime may be incarcerated, fined, or both. However, persons found liable in a civil case may only have to give up property or pay money, but are not incarcerated.