To analyze both the current arms debate and its roots, this report considers the schools of thought into which the debaters (the "Confronters," the "Disengagers," the "Interventionist Middle," and the "Noninterventionist Middle") are divided, and the key issues over which they differ: (1) the delineation of U.S. worldwide interests; (2) the causes of insurgency and other turmoil in the Third World and the effectiveness of various responses; and (3) the role of the United States in general and the U.S. military in particular in combating insurgency. The analysis examines these issues over four time periods: pre-Vietnam (the early 1960s), during Vietnam, Vietnam in retrospect (analyses published after the end of the conflict), and the present. The author identifies two major changes in American views on Third World policy that can be attributed to the Vietnam experience: Nobody now advocates U.S. military intervention in the Third World on a scale approaching that in Vietnam, and among those who do contemplate a possible need for some intervention somewhere in the future, there is recognition that major economic/political/social action must be coupled with the use of military force.