Criminal offenses are categorized according to the degree of their seriousness. In crimes against property, the seriousness of the crime is generally in proportion with the value of the property taken or damaged: the greater the property value, the more serious the crime. In crimes against persons, the same proportionality principle applies to bodily injury inflicted upon individuals: the greater the injury, the more serious the crime. A variety of other factors can influence the seriousness of a criminal offense, including whether the defendant had a prior criminal record, whether the defendant committed the crime with cruelty, malice, intent, or in reckless disregard of another person's safety, and whether the victim was a member of a protected class (e.g., minors, minorities, senior citizens, the handicapped, etc.). A less serious crime can be made more serious by the presence of these additional factors, and a more serious crime can be made less serious by their absence.
There are two categories of criminal offenses: felony, and misdemeanor, with misdemeanor being the less serious. Every U. S. jurisdiction retains the distinction between felony level criminal offenses and misdemeanor level offenses. However, most jurisdictions have added a third-tier of criminal offense, typically called an infraction or a petty offense. Although the definitions of all three classes differ from one jurisdiction to the next, they do share some common characteristics.
The power to define a crime and classify it as a felony, misdemeanor, or infraction rests solely with the legislature at the federal level. Federal courts do not have the power to punish any act that is not forbidden by federal statute. Most crimes made punishable by federal law are set forth in Title 18 U.S.C. sections 1 et seq.