  Historically, the use of coercion by powerful actors has been of great concern to philosophers and legal theorists. Detailed attention to understanding the concept coercion, however, is a relatively recent phenomenon. One effect of this discrepant attention is that it is sometimes difficult to determine what precise meaning earlier writers intended in their discussions of “coercion,” as well as to decide whether “coercion” captures something different from or related to other frequently used terms, such as violence, compulsion, punishment, force, or interference. A brief survey of a few notable thinkers suggests that coercion has commonly been understood as a use of a certain kind of power for the purpose of gaining advantages over others (including self-protection), punishing non-compliance with demands, and imposing one's will on the will of other agents. The kind of power needed for these functions is the sort that states and other forceful or violent agents possess. One of the clearest, most important uses of coercion has been understood to be the state's enforcement of law, either through direct uses of force or through punishments meted out to lawbreakers. The state's use of coercion is thought to be licensed in particular for the sake of preventing private acts of violence or coercion, as well as for punishing the failure to keep agreements. These public uses of coercion are thought justified because they make possible private cooperation and peaceable coexistence among people not linked by ties of affection or blood.