Victimless crimes can fall into a number of categories, including crimes without a clear victim, moral crimes, crimes against the state, or activities where the victim and the perpetrator could be considered the same person. In all cases, the government deems a particular activity a crime for health, safety, or social reasons, but it doesn't have an identifiable victim who experiences harm as a result of a perpetrator's actions. Some legislation pertaining to such crimes is controversial, and in some regions, reformers work to dismantle laws they feel are unfair or unnecessary.
Crimes without a clear victim involve cases where perpetrators cause harm, but no specific member of society is harmed by it. Rather, society as a whole pays the price. For example, when a person drives without car insurance, it exposes other drivers to risk, leading car insurance providers to raise prices to cover uninsured motorists. This crime affects society in general, but doesn't harm a specific person unless the uninsured motorist gets in an accident.
Moral crimes include activities classified as criminal for social or moral reasons; many nations, for example, historically barred sodomy between consenting adults on the grounds that it was an offense to common decency. Activities like vagrancy, public drunkenness, and loitering might also be social crimes. Many juvenile offenses fall under this category; society in general feels an obligation to care for juveniles and passes laws to protect them by requiring them to maintain beneficial behaviors like attending school. Breaking these laws does not actively harm anyone, but may not be desirable to other members of society.
Crimes against the state may also be considered victimless crimes, even though the state can end up paying damages or suffering harm. Tax fraud might be considered such a crime under this rubric, even though it costs the government money, because the government itself cannot be considered a victim. Conversely, crimes like rape are prosecuted as crimes against the state, but clearly have an identifiable victim.
Drug use, failing to exercise safety precautions, prostitution, gambling, and other activities that could place people in danger are also victimless crimes in the sense that they expose the victim to risk, but not anyone else. Some advocates propose taking these crimes out of the law books because they involve legislating personal behavior. These are among the most contentious victimless crimes, as some clearly do cause social harms; drug use, for example, can contribute to the development of violence as well as situations like driving under the influence and putting other people in danger. Likewise, prostitution may involve human trafficking and other harmful activities.