Torture was formally abolished by European governments in the nineteenth century, and the actual practice of torture decreased as well during that period. In the twentieth century, however, torture became much more common. None of the theories that explain the reduction of torture in the nineteenth century can explain its resurgence in the twentieth. This paper argues that the use of torture follows the same patterns in contemporary times as it has in earlier historical periods. Torture is most commonly used against people who are not full members of a society, such as slaves, foreigners, prisoners of war, and members of racial, ethnic, and religious outsider groups. Torture is used less often against citizens, and is only used in cases of extremely serious crimes, such as treason. Two general twentieth century historical trends have caused torture to become more common. First, an increase in the number and severity of wars has caused an increase of torture against enemy guerrillas and partisans, prisoners of war, and conquered civilian populations. Second, changes in the nature of sovereignty have caused an expansion in the definition of acts constituting treason.