At the beginning of 1967 the United States was engaged in a steadily expanding air and ground war in Southeast Asia. Since its inception in February 1965, Operation Rolling Thunder, the bombing campaign against North Vietnam, had escalated in the number and significance of its targets, inflicting major damage on transportation networks industry, and petroleum refining and storage facilities. Yetthe campaign showed no signs of achieving either of its stated objectives. The air attacks had not broken the Hanoi government’s will to continue the war, and they had not halted or appreciably hindered the flow of People's Army of Vietnam (PAVN) troops and supplies into South Vietnam. North Vietnam had been able to repair damage and develop substitutes for destroyed facilities rapidly enough to cou