At dawn on 21 January 1968 a wave of North Vietnamese troops descended upon the American airbase at Khe Sahn. For weeks the airfield had come under sporadic fire and bombardment from NVA artillery. US intelligence had been reporting that multiple regiments of North Vietnamese troops had penetrated into the region surrounding the airfield and were poised to strike at any time. For the next six months, American and South Vietnamese troops fought a vicious battle of attrition with the North Vietnamese defending the airfield, and nearly caused the United States to unleash its nuclear arsenal.
The Khe Sahn airfield was located just below the DMZ between North and South Vietnam. It had served as a Special Forces outpost in the early phase of American operations in Vietnam before being established as an anchor point for US Marine operations in the northern part of South Vietnam. In April 1967 the North Vietnamese launched their first offensive effort near Khe Sahn in what became known as the Hill Battles. Six regiments of the 325C Division were defeated by two battalions of the 3rd Marines and elements of the 9th Marines. Following the Hill Battles, a decision was made to further strengthen American presence at the Khe Sahn airbase, in hopes that it would instigate the North Vietnamese to fight a set piece battle with US forces.
When the NVA launched their full scale assault on the airbase in January 1968, Gen. Westmoreland was convinced a nuclear attack would persuade the Communists to call off their attack. Fearing the airbase would be overrun like the French airbase at Dien Bien Phu, Westmoreland pressed Pacific Command to use nuclear or chemical weapons to halt the assault. The effort failed, but not because of American refusal to use those types of weapons. Unclassified documents report that Defense Secretary Robert McNamara sent a memo to President Lyndon B. Johnson stating “Because of terrain and other conditions peculiar to our operations in South Vietnam, it is inconceivable that the use of nuclear weapons would be recommended there against either Viet Cong or North Vietnamese forces.”
An overland force of Marine and Army troops were able to launch a relief effort with Operation Pegasus in April. Heavy airstrikes continued throughout the region for the remainder of the siege as the base was evacuated, which finally occurred in July. The Khe Sahn airbase was dismantled and destroyed and US forces were withdrawn from the area. The battle marked a pivotal point in American policy in Vietnam. With the election of Richard Nixon in November 1968 a new strategy would be implemented in Vietnam that would help bring about the US withdrawal from the country. Vietnamization was the handing over of combat duties back to the South Vietnamese with the American’s returning to their advisory role. Within five years of the Battle of Khe Sahn, US troops would be out of Vietnam.