The costs of artillery: harassment and interdiction fire in the Vietnam War

Abstract

A type of artillery mission practiced by the United States Army since World War I, Harassment and Interdiction (H&I) fire proved controversial during the Vietnam War. Intentionally unobserved, H&I targeted suspected Viet Cong or North Vietnamese Army (NVA) routes and positions. These artillery missions engaged suspected targets with no more than a few rounds fired at random intervals throughout the night, and sometimes during the day, seeking to deny enemy freedom of movement and to destroy enemy morale. Unlike visually observed missions, or those acquired with sensors, H&I promised fewer benefits in a war without fronts and harbored a greater potential to harm Vietnamese civilians and their property. Nevertheless, the army leveraged its ability to project firepower and fired the majority of its missions and nearly half of its ammunition as H&I during 1966 and 1967. Beginning in October 1967, however, General William C. Westmoreland seriously questioned the effectiveness of H&I fire. As the Commander of the United States Military Assistance Command, Vietnam (MACV), he prompted a series of reforms that gradually, but significantly, reduced H&I before his June 1968 departure from Vietnam. His successor, General Creighton W. Abrams, implemented further significant cuts within three months of assuming command, but maintained H&I at nearly 10 percent of artillery ammunition expended until early 1970 when he nearly eliminated the practice. Although both Westmoreland and Abrams emphasized that poorly applied firepower could cause collateral damage, neither leader viewed H&I as inherently counterproductive to their pacification efforts. Indeed, both leaders responded to budgetary pressure, rather than concern over civilian casualties, when reducing H&I fire. Regarding the narrow issue of H&I reform, both commanders resembled one another more than they differed. Neither Westmoreland nor Abrams reduced H&I fire as part of a radical shift in strategy.