In common law legal systems, a felony is a serious crime, often contrasted with a misdemeanor. In the U.S. legal system, this distinction is principally made in criminal law, wherein the Federal government considers a misdemeanor crime punishable with five days to a year in jail, and a felony crime as punishable with a year or more in prison; infractions, lesser crimes, are punishable with five days or less jail time, or no jail time.
Most common law jurisdictions have abolished the distinction between felony and misdemeanor, (e.g. Crimes Act 1958 (Vic., Australia) s. 332B(1), Crimes Act 1900 (NSW., Australia) s. 580E(1)). Such jurisdictions have adopted other classifications, e.g. in Canada, Australia, Republic of Ireland, and the U.K., a crime is either a summary offence or an indictable offence.
Some offenses, though similar in nature, may be felonies or misdemeanors depending on the circumstances. For example, the illegal manufacture, distribution or possession of controlled substances may be a felony, although possession of small amounts may be only a misdemeanor. Possession of a deadly weapon may be generally legal, but carrying the same weapon into a restricted area such as a school may be viewed as a serious offense, regardless of whether or not there is intent to use the weapon.
"The common law divided participants in a felony into four basic categories: (1) first-degree principals, those who actually committed the crime in question; (2) second-degree principals, aiders and abettors present at the scene of the crime; (3) accessories before the fact, aiders and abettors who helped the principal before the basic criminal event took place; and (4) accessories after the fact, persons who helped the principal after the basic criminal event took place. In the course of the 20th century, however, American jurisdictions eliminated the distinction among the first three categories." Gonzales v. Duenas-Alvarez, 549 U.S. __ (2007) (citations omitted).
In some states, felonies are also classified (class A, B, etc.) according to their seriousness. In New York State, the classes of felonies are E, D, C, B, A-II, and A-I (the most severe). The number of classifications and the corresponding crimes vary by state and are determined by the legislature. Usually, the legislature also determines the maximum punishment allowable for each felony class; this avoids the necessity of defining specific sentences for every possible crime.
Civil sanctions imposed on United States citizens convicted of a felony in many states include the loss of competence to serve on a grand or petit jury or to vote in elections even after release from prison. While controversial, these disabilities are explicitly sanctioned by the Fourteenth Amendment to the United States Constitution, a Reconstruction-era amendment that deals with permissible state regulation of voting rights.
For state law convictions, expungement is determined by the law of the state. Few states do not allow expungement, regardless of the offense.
Federal law does not have any provisions for persons convicted of felonies in a federal United States district court to apply to have their record expunged. The only relief that an individual prosecuted in Federal Court may receive is a Presidential Pardon, which does not expunge the conviction, but rather grants relief from the civil disabilities that stem from it.