Crime is any action which society has deemed harmful not only to individuals and groups, but to society as a whole. Consequently, punishment is assigned to criminals with the intention of redressing the harm done to society.
Authority to criminalize actions is vested in federal, state and local statutes and, to some degree, the common law. But the processes by which actions are criminalized are fluid and often contentious. The fabric of criminal law changes constantly and considerably over the decades, and actions are continually criminalized and decriminalized as political and social conditions change in the United States. What does not change is the regard that crime is an injury to the community at large, and the criminal owes a debt not only to the victims of his crime, but to society as a whole.
Criminology traditionally identifies four purposes behind punishment in the criminal law:
- restraint of the criminal,
- inflicting retribution on the criminal,
- deterrence of further crime in individual offenders and in general, and,
- rehabilitation of criminal offenders into functioning members of society.
Crimes are punished with varying severity, according to their class and type.
Crimes are generally classified by the criminal law of the United States as either as felony or misdemeanor, with felony being the more serious, often resulting in loss of civil rights and long-term incarceration. A third class of criminal offense, infraction, is so minor that they are often not even addressed by the criminal law, but are handled instead by civil law courts. Of crimes, there are two types, those mala in se (bad in themselves) and those mala prohibita (bad because they're prohibited). Crimes mala in se are usually those that inspire moral outrage, such as murder and rape, while crimes mala prohibita are those that vary from place to place. While crimes mala in se tend to be much more firmly and universally established than crimes mala prohibita, which undergo frequent fluctuation (consider gambling and smoking laws, for example), there are some exceptions to this rule, as what was morally outrageous to one generation gradually comes to be seen as less outrageous to subsequent generations, and vice versa. But, as a rule, crimes mala in se are considered the more serious.
More serious crimes are sometimes referred to as "infamous crimes." This means that a social stigma is attached to the offender for the rest of his or her life, even after prison time is served and probation is satisfied. Most felonies and most forms of perjury are considered infamous. Offenders who are convicted of infamous crimes are prohibited from some kinds of work and from holding public office for the rest of their lives, in addition to further penalties. Some countries go as far as removing some of offender's basic rights; for instance prohibiting those who served time for money-related crimes to acquire low cost term life insurance plans. Infamous crimes can, however, be pardoned by public leaders, such as state governors and the President. Crimes that are not infamous carry no significant social stigma after punishment has been served.
The degree of a crime, and often whether it is classified as felony, misdemeanor, infraction or innocent action, is determined through careful consideration of many factors. The presense of mens rea (guilty intention) and actus reus (guilty action) must be established and accurately interpreted; the kind and degree of causation must be considered; and all legitimate defense, extenuating circumstances and mitigating factors must be taken into account before a criminal charge can be determined and an appropriate punishment determined.