President Lyndon Johnson reluctantly began the sustained bombing of North Vietnam with Operation Rolling Thunder on March 2, 1965. Johnson initially thought that gradually increasing attacks against the North Vietnamese heartland might break the North’s morale and end its support of the insurgency, but the significant restrictions that the president placed on bombing limited its effectiveness. More importantly, the character of the war fought by the Viet Cong and the North Vietnamese – an infrequently waged guerrilla conflict that required minimal supplies to wage – negated the utility of bombing the North’s supply lines, oil, and its meager amount of industry. Meanwhile, in South Vietnam, air force, navy, and marine fighters and helicopters supported American and South Vietnamese ground operations, as did US Air Force B-52s, which began bombing Southern targets in a massive campaign known as Arc Light in June 1965. Compared to bombing the North, air attacks on South Vietnamese territory had few limitations and often inflicted significant civilian casualties. Though air power often tilted the scales toward American forces in rare conventional engagements like Khe Sanh and the Tet Offensive, it could not guarantee survival of a Southern government that was fundamentally corrupt and out of touch with its populace.

Chapter 4 evaluates US tactical air power from 1967 to 1968. Over North Vietnam, the Rolling Thunder air interdiction campaign struggled to isolate NVA/VC forces. Simultaneously, a strategic bombing campaign could not coerce Hanoi to withdraw its support of the insurgency. The direct attack of the NVA/VC forces in South Vietnam proved more effective, with the ultimate test occurring near the demilitarized zone (DMZ) at the US Marine base at Khe Sanh. Here, the NVA massed two divisions hoping to overrun the marines to achieve a decisive victory as they had against the French in 1954 at Dien Bien Phu. Instead, the American combined arms campaign defeated the NVA. The massing of ground forces at Khe Sanh differed from the NVA’s previous tactics of dispersing and taking sanctuary in Laos and Cambodia. Such defensive measures had previously allowed the NVA/VC to survive but had also delayed plans to launch a General Offensive and General Uprising. When the NVA/VC finally commenced their offensive in early 1968, they failed militarily at Khe Sanh and, more broadly, in the Tet Offensive. However, more importantly, the North Vietnamese succeeded politically as American support for the war evaporated.