In 2009 the American Public Health Association approved the policy statement, "The Role of Public Health Practitioners, Academics, and Advocates in Relation to Armed Conflict and War." Despite the known health effects of war, the development of competencies to prevent war has received little attention. Public health's ethical principles of practice prioritize addressing the fundamental causes of disease and adverse health outcomes. A working group grew out of the American Public Health Association's Peace Caucus to build upon the 2009 policy by proposing competencies to understand and prevent the political, economic, social, and cultural determinants of war, particularly militarism. The working group recommends that schools of public health and public health organizations incorporate these competencies into professional preparation programs, research, and advocacy.