<P> After the Malayan conflict ended in 1960, the U.S. considered the British precedent in deciding that the use of defoliants was a legal tactic of warfare . Secretary of State Dean Rusk advised President John F. Kennedy that the British had established a precedent for warfare with herbicides in Malaya . </P> <P> In mid-1961, President Ngo Dinh Diem of South Vietnam asked the United States to conduct aerial herbicide spraying in his country . In August of that year, the Republic of Vietnam Air Force conducted herbicide operations with American help . But Diem's request launched a policy debate in the White House and the State and Defense Departments . However, U.S. officials considered using it, pointing out that the British had already used herbicides and defoliants during the Malayan Emergency in the 1950s . In November 1961, President John F. Kennedy authorized the start of Operation Ranch Hand, the codename for the U.S. Air Force's herbicide program in Vietnam . </P> <P> During the Vietnam War, between 1962 and 1971, the United States military sprayed nearly 20,000,000 U.S. gallons (76,000 m) of various chemicals--the "rainbow herbicides" and defoliants--in Vietnam, eastern Laos, and parts of Cambodia as part of the aerial defoliation program known as Operation Ranch Hand, reaching its peak from 1967 to 1969 . For comparison purposes, an olympic size pool holds approximately 660,000 U.S. gal (2,500 m). As the British did in Malaya, the goal of the US was to defoliate rural / forested land, depriving guerrillas of food and concealment and clearing sensitive areas such as around base perimeters . The program was also a part of a general policy of forced draft urbanization, which aimed to destroy the ability of peasants to support themselves in the countryside, forcing them to flee to the U.S. - dominated cities, depriving the guerrillas of their rural support base . </P> <P> Agent Orange was usually sprayed from helicopters or from low - flying C - 123 Provider aircraft, fitted with sprayers and "MC - 1 Hourglass" pump systems and 1,000 U.S. gallons (3,800 L) chemical tanks . Spray runs were also conducted from trucks, boats, and backpack sprayers . </P>

What was agent orange used for in the vietnam war