A sanction is an action by one actor (A) intended to affect the behavior of another actor (B) by enhancing or reducing the values available to B. Influence attempts by A using actual or threatened punishments of B are instances of negative sanctions. Influence attempts by A using actual or promised rewards to B are instances of positive sanctions. Until the mid-twentieth century, sanctions were viewed primarily as mechanisms for enforcing societal norms, including those embedded in laws. Although this normative view of sanctions continues in legal theory, ethics, political theory, and sociology, a broader usage has emerged in political science during the latter part of the twentieth century. This broader usage depicts sanctions as potentially relevant to any type of influence attempt. This usage is typically found in discussions of influence and power. The subfield of political science that has devoted the most attention to sanctions in recent years is international relations and foreign policy. Most of this research has focused on the use of economic sanctions as foreign policy tools. Here, as elsewhere in political science, more attention has been devoted to negative sanctions than to positive ones.