Coercive Air Power in the Vietnam War

I I n the years since World War 11, social scientists have devoted considerable attention to the problem of military coercion.’ This interest is due in part to nuclear weapons, which are seen as better suited to inflicting punishment on civilian societies than to attacking battlefield targets directly. However, coercion is also important in purely conventional conflicts, because states may still conduct strategic air offensives against their adversaries. The American bombing of Vietnam is a classic example of conventional coercion. Throughout the war, the United States used its powerful air forces to strike at the North Vietnamese homeland, for the purpose of altering Hanoi’s behavior on the battlefield and position at the negotiating table. Although the desirability of bombing the North generated heated debate at the time, the task here is to use this case to identify when coercion will succeed or fail.2 I greatly appreciate the careful comments of Daniel Bolger, Michael Brown, John Chapman, Michael Desch, Brian Downing, Matthew Evangelista, ScottGartner, Charles Glaser, Paul Huth, Chaim Kaufmann, Craig Koerner, John Mearsheimer, Wayne Thompson, Marc Trachtenberg, Stephen Van Evera, Andrew Wallace, Stephen Walt, and William Zimmerman. I also would like to thank members of the Program on International Politics, Economics, and Security (University of Chicago), the Military History Workshop (University of Michigan) and the National Security Seminar (Harvard University), and an anonymous reviewer. The United States Air Force Historical Research Center, Maxwell Air Force Base, Ala., provided valuable support. Robert A. Pape, Jr., is a John D. and Catherine T. MacArthur Post-doctoral Fellow in the Program for Znternational Peace and Security Research, University of Michigan. He is currently completing a book on coercive bombing and bargaining. 1. The landmark studies of military coercion in the nuclear age are: Daniel Ellsberg, “Theory and Practice of Blackmail,” P-3883 (Santa Monica, Calif.: RAND,1968); Morton Kaplan, The Strategy of Limited Retaliation, Center of International Studies Policy Memorandum No. 19, Princeton University, April 9, 1959;J. David Singer, ”Inter-Nation Influence: A Formal Model,” American Political Science Review, Vol. 56, No. 2 (June, 1963), pp. 420-430; Thomas C. Schelling, Arms and Znfluence (New Haven: Yale University Press, 1966); Alexander L. George, David K. Hall, and William E. Simons, The Limits of Coercive Diplomacy: Laos, Cuba and Vietnam (Boston: Little, Brown, 1971); and Richard K. Betts, Nuclear Blackmail and Nuclear Balance (Washington, D.C.: Brookings, 1987). 2. Debate on the air war against North Vietnam focuses principally on the conditions under which coercion is effective. The most extreme position holds that coercion is likely to fail under almost any set of circumstances: Wallace J. Thies, When Governments Collide: Coercion and Diplomacy in the Vietnam Conflict 1964-1968 (Berkeley: University of California Press, 1980); Andrew Pierre, “America Down, Russia Up: The Changing Political Role of Military Power,” Foreign ~ International Security, Fall 1990(Vol. 15, No. 2) 0 1990 by the President and Fellows of Harvard College and of the MassachusettsInstitute of Technology. 203 International Security 15:2 I 104 This article, first, outlines a theory of coercion that identifiesthe conditions under which coercive attacks are likely to be effe~tive.~ Second, it compares this new theory’s predictions with the failures and successes of different American air offensives against North Vietnam. The accepted wisdom is that successful coercion rests on the threat to destroy vulnerable civilian target^.^ This logic is assumed to apply to both the nuclear and conventional realms. In contrast, I argue that successful coercion, at least in conventional wars, results from the use of air power to exploit the opponent’s military vulnerabilities, thereby making it infeasible for the opponent to achieve his political goals by continued military efforts. As developed at length below, the air war against North Vietnam suggests that it is military impact, not civilian vulnerability, that provides the critical leverage in conventional coercion. The United States conducted four distinct bombing campaigns against North Vietnam. The first was Lyndon Johnson’s “Rolling Thunder” campaign, which ran from March 2, 1965, through October 31, 1968. The principal goals were to coerce the North Vietnamese into Policy, No. 4 (Fall 1971),pp. 163-187; and Colin S. Gray, ”What RAND Hath Wrought,” Foreign Policy, No. 4...