Events in Southeast Asia after the Vietnam War

Aftermath of Vietnam War: Phnom Penh, the capital of Cambodia, fell to followers of the Communist Party of Kampuchea, commonly known as the Khmer Rouge, on 17 April 1975. Over the next four years, the Khmer Rouge enacted a genocidal policy that killed over one-fifth of all Cambodians, or more than a million people. After repeated border clashes in 1978, Vietnam invaded Democratic Kampuchea (Cambodia) and ousted the Khmer Rouge in the Cambodian–Vietnamese War.

In response, China invaded Vietnam in 1979. The two countries fought a brief border war, known as the Third Indochina War or the Sino-Vietnamese War. From 1978 to 1979, some 450,000 ethnic Chinese left Vietnam by boat as refugees or were expelled across the land border with China.

The Pathet Lao overthrew the royalist government of Laos in December 1975. They established the Lao People's Democratic Republic.[215] From 1975 to 1996, the United States resettled some 250,000 Lao refugees from Thailand, including 130,000 Hmong.

More than 3 million people fled from Vietnam, Laos, and Cambodia, many as "boat people". Most Asian countries were unwilling to accept refugees. Since 1975, an estimated 1.4 million refugees from Vietnam and other Southeast Asian countries have been resettled to the United States, while Canada, Australia, and France resettled over 500,000.

Effect of Vietnam War on the United States

Aftermath of Vietnam War: In the post-war era, Americans struggled to absorb the lessons of the military intervention. As General Maxwell Taylor, one of the principal architects of the war, noted "first, we didn't know ourselves. We thought that we were going into another Korean War, but this was a different country. Secondly, we didn't know our South Vietnamese allies... And we knew less about North Vietnam. Who was Ho Chi Minh? Nobody really knew. So, until we know the enemy and know our allies and know ourselves, we'd better keep out of this kind of dirty business. It's very dangerous."

Some have suggested that "the responsibility for the ultimate failure of this policy [America's withdrawal from Vietnam] lies not with the men who fought, but with those in Congress..." Alternatively, the official history of the United States Army noted that "tactics have often seemed to exist apart from larger issues, strategies, and objectives. Yet in Vietnam the Army experienced tactical success and strategic failure. The Vietnam War legacy may be the lesson that unique historical, political, cultural, and social factors always impinge on the military. Success rests not only on military progress but on correctly analyzing the nature of the particular conflict, understanding the enemy's strategy, and assessing the strengths and weaknesses of allies. A new humility and a new sophistication may form the best parts of a complex heritage left to the Army by the long, bitter war in Vietnam."

U.S. Secretary of State Henry Kissinger wrote in a secret memo to President Gerald Ford that "in terms of military tactics, we cannot help draw the conclusion that our armed forces are not suited to this kind of war. Even the Special Forces who had been designed for it could not prevail." Even Secretary of Defense Robert McNamara concluded that "the achievement of a military victory by U.S. forces in Vietnam was indeed a dangerous illusion."

Doubts surfaced as to the effectiveness of large-scale, sustained bombing. As Army Chief of Staff Harold Keith Johnson noted, "if anything came out of Vietnam, it was that air power couldn't do the job. Even General William Westmoreland admitted that the bombing had been ineffective. As he remarked, "I still doubt that the North Vietnamese would have relented."

The inability to bomb Hanoi to the bargaining table also illustrated another U.S. miscalculation. The North's leadership was composed of hardened communists who had been fighting for independence for thirty years. They had successfully defeated the French, and their tenacity as both nationalists and communists was formidable. Ho Chi Minh is quoted as saying, "You can kill ten of my men for every one I kill of yours...But even at these odds you will lose and I will win."

The Vietnam War called into question the U.S. Army doctrine. Marine Corps General Victor H. Krulak heavily criticized Westmoreland's attrition strategy, calling it "wasteful of American lives... with small likelihood of a successful outcome." As well, doubts surfaced about the ability of the military to train foreign forces.

Between 1965 and 1975, the United States spent $111 billion on the war ($686 billion in FY2008 dollars). This resulted in a large federal budget deficit.

More than 3 million Americans served in the Vietnam War. By war's end, 58,193 soldiers were killed, more than 150,000 were wounded, and at least 21,000 were permanently disabled. 61% of the men killed were age 21 or younger. Of those killed in combat, 86.3% were white, 12.5% were black and 1.2% from other races. Approximately 830,000 Vietnam veterans suffered symptoms of post-traumatic stress disorder. An estimated 125,000 Americans fled to Canada to avoid the Vietnam draft, and approximately 50,000 American servicemen deserted. In 1977, United States President Jimmy Carter granted a full, complete and unconditional pardon to all Vietnam-era Draft dodgers. The Vietnam War POW/MIA issue, concerning the fate of U.S. service personnel listed as missing in action, persisted for many years after the war's conclusion.

Chemical defoliation

Aftermath of Vietnam War: One of the most controversial aspects of the U.S. military effort in Southeast Asia was the widespread use of chemical defoliants between 1961 and 1971. They were used to defoliate large parts of the countryside. These chemicals continue to change the landscape, cause diseases and birth defects, and poison the food chain.

Early in the American military effort it was decided that since the enemy were hiding their activities under triple-canopy jungle, a useful first step might be to defoliate certain areas. This was especially true of growth surrounding bases (both large and small) in what became known as Operation Ranch Hand. Corporations like Dow Chemical Company and Monsanto were given the task of developing herbicides for this purpose.

The defoliants, which were distributed in drums marked with color-coded bands, included the "Rainbow Herbicides"—Agent Pink, Agent Green, Agent Purple, Agent Blue, Agent White, and, most famously, Agent Orange, which included dioxin as a by-product of its manufacture. About 12 million gallons (45,000,000 L) of Agent Orange were sprayed over Southeast Asia during the American involvement. A prime area of Ranch Hand operations was in the Mekong Delta, where the U.S. Navy patrol boats were vulnerable to attack from the undergrowth at the water's edge.

In 1961 and 1962, the Kennedy administration authorized the use of chemicals to destroy rice crops. Between 1961 and 1967, the U.S. Air Force sprayed 20 million U.S. gallons (75,700,000 L) of concentrated herbicides over 6 million acres (24,000 km2) of crops and trees, affecting an estimated 13% of South Vietnam's land. In 1965, 42% of all herbicide was sprayed over food crops. Another purpose of herbicide use was to drive civilian populations into RVN-controlled areas.

As of 2006, the Vietnamese government estimates that there are over 4,000,000 victims of dioxin poisoning in Vietnam, although the United States government denies any conclusive scientific links between Agent Orange and the Vietnamese victims of dioxin poisoning. In some areas of southern Vietnam dioxin levels remain at over 100 times the accepted international standard.

The U.S. Veterans Administration has listed prostate cancer, respiratory cancers, multiple myeloma, Diabetes mellitus type 2, B-cell lymphomas, soft tissue sarcoma, chloracne, porphyria cutanea tarda, peripheral neuropathy, and spina bifida in children of veterans exposed to Agent Orange. Although there has been much discussion over whether the use of these defoliants constituted a violation of the laws of war, the defoliants were not considered weapons, since exposure to them did not lead to immediate death or incapacitation.