When the two-sided four-party Paris peace talks began in early 1969, it was quickly apparent that they were little more than a propaganda platform. Hanoi was occupied with rebuilding its military capability in the south without the large southern component that had been sacrificed in 1968 and was content to delay serious negotiations until it had gained a stronger position on the battlefield. Under strong political pressure to end American involvement in the war and with the Paris negotiations at an impasse, the new administration of Richard Milhous Nixon (1913–1994) shifted to a strategy of removing American forces from Vietnam and giving responsibility for the anti-communist struggle back to the South Vietnamese. This was possible because the Second Republic government in Saigon was stable and enjoyed a relatively high measure of popular support, and also because the communist defeats in 1968 had temporarily, but significantly, reduced the battlefield threat.
Secretary of Defense Melvin Robert Laird (b. 1922) made plans to redeploy nearly all American military forces out of Vietnam by the end of 1972. The first redeployment was announced in the summer of 1969 and the drawdown continued thereafter on schedule. General Creighton Williams Abrams, Jr. (1914–1974), who replaced Westmoreland in 1968, espoused a new strategy of “one war,” which aimed to integrate the operations of the Vietnamese and American armies and also to integrate civilian and military operations.
Under Westmoreland’s command, the Vietnamese army was for the most part pushed aside from battlefield responsibilities as American forces conducted search and destroy operations. Furthermore, the equipment provided by the Americans to the Vietnamese was generally inferior to that available to commun- ist forces, particularly in the quality of small arms and individual weapons. Under Abrams, the South Vietnamese army was equipped with up-to-date weapons that were equivalent to the quality of arms used by its enemy. Abrams organized joint Vietnamese–American operations that were to some extent designed as training exercises. As American redeployment progressed, the Viet- namese increasingly assumed responsibility for defending the country. At the same time, American programs for assisting civilians in battle zones that from 1967 had begun to be integrated into American military operations were turned over to the Vietnamese. These policies, commonly referred to as “Vietnamiza- tion,” needed time for implementation, and major campaigns in Cambodia and Laos during 1970 and 1971 aimed to gain time by keeping communist forces off balance and away from South Vietnamese cities
. In early 1970, the Cambodian army commander, Lon Nol, who opposed the arrangements that had allowed the Vietnamese communists to use Cambodian territory, deposed Sihanouk. Sihanouk then joined a Chinese-sponsored alliance between the Vietnamese and Cambodian communists as Lon Nol appealed to the US for assistance. South Vietnamese and American forces advanced into Cam- bodia, forcing the Vietnamese communists to evacuate their headquarters and supply bases. These events were accompanied by widespread massacres of Viet- namese residing in Cambodia, victims of Cambodian resentment against the dominance of Vietnamese communists that Sihanouk had allowed in the eastern part of the country. Americans and South Vietnamese believed that this oper- ation, which continued into the summer of 1970, helped to keep Vietnamese battlefields relatively quiet for a year, enabling the Vietnamization process to gain momentum. Opposition to this operation in the US Congress, however, resulted in a law prohibiting American ground troops from thereafter entering Cambodia or Laos.
War continued between Lon Nol and the Cambodian and Vietnamese com- munist forces, but the port of Sihanoukville was thereafter closed to the com- munists, and North Vietnam became more dependent upon its supply lines through southern Laos. In early 1971, South Vietnamese forces entered southern Laos in an operation designed to sever the communist supply lines during the winter dry season. In a series of battles, North and South Vietnamese forces both suffered heavy casualties. Although the initial aim of the operation was not fully reached, North Vietnamese plans were sufficiently disrupted to give the Vietnamization policy another year of relative calm. By early 1972, the number of US ground troops in Vietnam was insignificant and the American presence had become more like the Kennedy phase of advising with logistical and air support.
At the international level, Nixon endeavored to exploit the deepening Sino- Soviet dispute by diplomatically engaging each of these major communist powers and persuading them that they had more to gain from strengthening relations with the US than from supporting the North Vietnamese. Nixon understood that the Cold War was shifting from a bipolar confrontation toward a three-corner game with possibilities for prying one or both of the communist powers away from Hanoi. China had begun to withdraw its troops from North Vietnam after the end of American bombing and the beginning of American redeployment, and it began to be apparent that the Chinese were not in favor of Hanoi gaining control of South Vietnam. While China had supported Hanoi so long as the American presence in South Vietnam was on a threatening scale, it was not keen to have a united Vietnam on its southern border. On the other hand, the Soviet Union was ready to provide Hanoi with all that it needed to conquer the south and thereby gain a potential ally in the increasingly rancorous confrontations that were characterizing Sino-Soviet relations.
The troubled state of Sino-Soviet relations made both powers want to strengthen ties with the US in order to isolate the other. Nixon enjoyed the benefit of China and of the Soviet Union competing to build strategic relation- ships with the US. There were plans for Nixon to visit both countries during the first half of 1972. Le Duan understood that the international situation was changing in a direction that threatened to downgrade the importance of North Vietnam to its allies and decided to try for a quick military victory.